Q & A. [interview

Joel Rosenbaum was born and grew up in Massena, New York state, on the St Lawrence River border with Ontario, Canada. He received his undergraduate and PhD degrees from Syracuse University, and a Masters Degree in high school biology teaching at St Lawrence University. His PhD work was done with the protozoologist, George Holz Jr, and his post doctoral research on cilia and flagella was at the University Of Chicago with Frank Child and Hewson Swift. He has been at Yale University for 37 years where he has taught Cell Biology. His research has been on the synthesis and assembly of the proteins of cilia and flagella, showing that the flagellar axoneme assembles at the distal tip and that detachment of the flagella upregulates the genes for flagellar proteins. More recently his group has shown that this tip assembly process is facilitated by a rapid kinesin and cytoplasmic dynein-mediated motility underneath the flagellar membrane called ‘intraflagellar transport’. He is a runner with more than 20 marathons under his belt.     

Q & A. [interview

George Oster is Professor of Biophysics, University of California, Berkeley. He received his B.S. at the U.S. Merchant Marine Academy and his Ph.D. at Columbia University. He began his career in biophysics as a postdoc at the Weizmann Institute under Aharon Katchalsky, where his research involved membrane biophysics and irreversible thermodynamics. His concern for environmental issues led him into population biology, which shaded into evolutionary biology and thence to developmental biology, cell biology and, most recently, protein motors and bacterial motility and pattern formation. His tools are mathematics, physics and computer simulation. He is currently a faculty member in the Departments of Molecular and Cellular Biology and the College of Natural Resources at Berkeley.     

An interview with Dr. Frank Slack on his highly cited paper published in Cell Cycle

Frank Slack received his B.Sc from the University of Cape Town in South Africa, before completing his Ph.D in molecular biology at Tufts University School of Medicine. He started work on microRNAs as a postdoctoral fellow in Gary Ruvkun’s laboratory at Harvard Medical School, where he co-discovered the second known microRNA, let-7. He is currently an Associate Professor in the Department of Molecular, Cellular and Developmental Biology at Yale University. The Slack laboratory studies the roles of microRNAs and their targets in development, disease and aging.     

Q & A: Till Roenneberg

Till Roenneberg is Professor of Chronobiology at the University of Munich. He studies the circadian clock from its cellular/molecular mechanisms up to the consequences of shift work. He received his education in Munich and London, and worked in the 1980s with Woody Hastings at Harvard. Since then, he has built up the Centre for Chronobiology at the Munich Medical School. For many years, he has coordinated circadian research and education in Germany and in Europe. He is also involved in reforming the University curriculum, incorporating problem-based approaches. He has received international prizes for both his research and his teaching.     

Henk van den Bosch: chemist and biochemist

Henk van den Bosch is a native of The Netherlands and recently retired from his position as Professor at Utrecht University. This article summarizes the many scientific achievements of Dr. van den Bosch. He enjoys an international reputation for his research on phospholipases A, cardiolipin biosynthesis in eukaryotes, lysophospholipases, phosphatidylcholine biosynthesis for lung surfactant, plasmalogen biosynthesis in peroxisomes, diagnosis of peroxisomal disorders and most recently his work on alkyl-dihydroxyacetone phosphate synthase. During his research career Henk van den Bosch published approximately 280 articles and presented 110 invited lectures.     

The Role of Binding Energy in Catalysis: the Work of William P. Jencks

Two Functional Domains of Coenzyme A Activate Catalysis by Coenzyme A Transferase. Pantetheine and Adenosine 3′-Phosphate 5′-Diphosphate (Fierke, C. A., and Jencks, W. P. (1986) J. Biol. Chem. 261, 7603–7606)William Platt Jencks (1927–2007) was born in Bar Harbor, Maine. He became interested in chemistry when he received a chemistry set for Christmas in 1934. He immediately carried out one of the experiments described in the instructions, the addition of dilute acid to a sulfide salt to produce H₂S. The experiment was so successful that his house had to be evacuated due to the smell of rotten eggs. According to Jencks, “My family and I did not find it necessary to replicate this experiment” (1).Open in a separate windowWilliam P. JencksJencks enrolled at Harvard College, intending to study chemistry. However, after taking a first year course in chemistry that “described a large number of chemical reactions, one after the other, with no indication of what was interesting about any of them” (1), he switched his major to English. Despite this change in the direction of his studies, Jencks ended up entering Harvard Medical School after his junior year because he wasn''t sure what else to do.After completing his first year of medical school, Jencks spent a summer at the Marine Biological Laboratory in Woods Hole, taking courses and doing research on lobster shell pigments with Journal of Biological Chemistry (JBC) Classic author George Wald (2). He received his M.D. in 1951 and then interned at Peter Bent Brigham Hospital in Boston. However, after a while, Jencks found medicine to be “a very broad field in which it would be difficult to obtain definitive answers to fundamental problems” (1). Wald suggested Jencks try doing research at Massachusetts General Hospital with Nobel laureate Fritz Lipmann (who was featured in a previous JBC Classic (3)). Jencks ended up spending 2 years with Lipmann, studying coenzyme A transferase, which led to his longtime interest in the physical organic chemistry of acyl transfer reactions. After leaving Massachusetts General Hospital, Jencks spent a year doing postdoctoral studies at Harvard University with Nobel laureate Robert Woodward before joining the faculty at Brandeis University in 1957, serving as assistant, associate, and then full professor of biochemistry. He retired in 1996 as professor emeritus of biochemistry.During his 39 years at Brandeis University, Jencks studied the mechanisms by which enzymes facilitate chemical reactions of molecules that are not otherwise inclined to react at a useful rate.The JBC Classic reprinted here looks at the noncovalent interactions between succinyl-CoA 3-ketoacid coenzyme A transferase and coenzyme A. In the paper, Jencks and Carol A. Fierke used a small coenzyme A analog, methylmercaptopropionate, to show that noncovalent interactions between the enzyme and the side chain of CoA are responsible for the reaction rate increase brought about by the enzyme. They report that interaction between the enzyme and the pantetheine moiety of CoA provides the majority of substrate destabilization and rate acceleration, whereas the interaction with the 3′-phospho-ADP1 moiety provides binding energy that overcomes this destabilization and permits significant binding of acyl-CoA substrates to the enzyme. This paper helped to illuminate a striking example of the role of binding energy in catalysis.Jencks received many honors and awards for his contributions to science, including memberships in the National Academy of Sciences (1971) and the American Philosophical Society (1995) and foreign membership in the Royal Society. He also received the 1962 American Chemical Society (ACS) Award in Biological Chemistry, the 1993 American Society of Biological Chemists Award, the 1995 ACS James Flack Norris Award in Physical Organic Chemistry, and the 1996 ACS Repligen Award for Chemistry of Biological Processes.¹     

Hunters and Horticulturalists: A Preliminary Report of the 1972–4 Excavations in the Manim Valley,Papua New Guinea

Ole Christensen, a PhD scholar in the Department of Prehistory in the Research School of Pacific Studies at the Australian National University, was killed in a car accident on his way to work on 16 December last year. Ole was a Canadian citizen of Danish birth, whose parents settled in rural Alberta. He took his BA(Hons) in 1970 and his MA in 1972, both in the Department of Archaeology at the University of Calgary. His MA thesis, ‘Banff Prehistory: prehistoric subsistence and settlement in Banff National Park, Alberta’, is evidence of an early interest in economically and ecologically oriented archaeology, which he furthered by taking courses and laboratory work in pollen analysis. A visit to South America in 1970 with an archaeological team investigating early farming settlements in the Cauca Valley, Colombia, combined with a long standing interest in Polynesian anthropology to encourage him to seek to do graduate work on tropical agricultural systems somewhere in the Pacific. When he subsequently applied for the ANU scholarship which he took up in early 1972, he seemed a highly suitable person to work in association with the Department of Prehistory's project into New Guinea Highlands' agricultural history then about to start at Kuk in the upper Wahgi valley (see Mankind, 3:177–83). The proposition put to Ole was that he should undertake a study of the hydraulic technology and agrarian organization of one of the large scale agricultural systems operating in drained swamp that still flourish in Irian Jaya at the Paniai (Wissel) Lakes and in the Baliem valley, to supplement the archaeological work in the Wahgi where such systems had once but no longer existed. He felt, however, that his ethnographic background was too slim and he chose instead to do work for which he was better trained, the study of resource utilization over time in a side valley off the Wahgi close to the site of the Department's swamp excavations. The beautifully designed project that he carried out is described in the following article by him. It is based on a seminar he gave at ANU shortly before his death. I should like to make two points about this project that the article does not stress. One is the wealth of plant materials recovered from the excavations by wet sieving every ounce of excavated soil, when the nearest water source was sometimes some hundreds of precipitous yards away. The abundant pandanus seeds found in all levels of the excavated sites and their change over time from thick-walled, allegedly wild, to thin-walled, allegedly cultivated, varieties may hold important evidence for the chronology of horticulture in New Guinea and the question of whether an independent development of plant domestication took place there. The second point I want to make is that against his expectations he found himself to be a born and insatiable ethnographic fieldworker. With his Wurup friends he surveyed and recorded all the resource zones in terms of which his selection of sites for excavation was made and took part in all the activities of food procurement and processing that were responsible for the archaeological evidence that he set out to recover and interpret. A practical man of quiet and simple tastes, he was as settled in his bush house at Wurup as in his rural retreat near Canberra. He was unassertive, tolerant and deeply sympathetic and made undemanding and unobtrusive friendships with people in both homes. He is a loss to them and to his profession. His colleagues at the University of Calgary are establishing an academic prize in his memory. To his colleagues at ANU falls the responsibility of ensuring that the important work of this promising young scholar is brought to completion.     

祝贺生物化学家、营养学家郑集教授百岁华诞

郑集是我国老一辈著名的生物化学家、营养家家 ,是我国生物化学、营养学的先导者之一 ,衰老生物化学的主要奠基者 .郑集 1 90 0年生于四川省南溪县农村 ,家境贫寒 .他的童年和青年时期都是在贫病交加的情况下度过的 .他没有读过正规中学 ,他克服难以想象的困难考入南京东南大学 (后改为中央大学 ) ,1 92 8年毕业 .后来 ,他有幸出国深造 ,1 934年获美国印第安那大学博士学位 .当即回国 ,开始他的教学和蛋白质化学、营养学的研究工作 .1 937～ 1 946年学校因抗战西迁四川 ,尽管条件极度困难 ,他在工作之余还著书立说 ,创办杂志和筹建学会 .抗战胜利后 ,回到南京重建实验室 ,奋力工作 .1 949年解放以后 ,郑集先后在南京大学 (原名中央大学 )、军医大学和调整后的南京大学工作至今 .1 957年在南京大学建立生物化学专业 ,培养了许多专业人才 .70年代初开辟衰老生化机制的研究 ,提出代谢失调学说 .已经发表的论文和著作达 30 0篇 /本 ,获得国内外荣誉证书和奖状等 50多件 .郑集工作勤奋 ,孜孜不倦 ,几乎将节假日都用来工作 .他性格顽强 ,不怕困难 ,勇于做开创性的工作 .他讲课内容丰富 ,善于启发 ,被学生誉为艺术享受 .他对学生和青年教师全面关心 ,要求严格 ,许多学生畏而敬之 .他生活俭朴 ,品德高尚 ,他将仅     

Philip Cohen

Philip Cohen trained at University College London and, after postdoctoral research at the University of Washington, joined the University of Dundee Scotland, in 1971, where he has worked ever since. He is a Royal Society Research Professor and Director of the Medical Research Council Protein Phosphorylation Unit. His main contributions have been in the area of protein phosphorylation and its role in cell regulation and human disease. In 1998, he was knighted for his contributions to biochemistry and the development of Life Sciences at Dundee.     

Multienzyme Complexes and Hydrogen Transfer: the Work of Perry Frey

Quaternary Structure of Pyruvate Dehydrogenase Complex from Esherichia coli(Yang, H. C., Hainfeld, J. F., Wall, J. S., and Frey, P. A. (1985) J. Biol. Chem. 260, 16049–16051)Lysine 2,3-Aminomutase. Support for a Mechanism of Hydrogen Transfer Involving S-Adenosylmethionine(Baraniak, J., Moss, M. L., and Frey, P. A. (1989) J. Biol. Chem. 264, 1357–1360)Perry A. Frey was born in 1935 in Plain City, Ohio, a small town about 18 miles northwest of Columbus. Prior to attending college he served in the military for 2 years. He then enrolled at Ohio State University where he received his B.S. in chemistry in 1959. After graduating, Frey worked for the United States Public Health Service as an analytical chemist, studying the properties of saxitoxin, a paralytic shellfish poison. He also attended night classes in chemistry at the University of Cincinnati.Open in a separate windowPerry FreyIn 1964, based on the recommendation of a mentor at the Public Health Service, Frey decided to go to graduate school at the University of Michigan to work with Robert H. Abeles. After a short time, Abeles moved his laboratory to Brandeis University and Frey went with him. Frey spent 3 years studying catalysis by cobalamin-dependent enzymes and earned his Ph.D in biochemistry in 1968. He then began a postdoctoral fellowship at Harvard University with enzymologist Frank H. Westheimer.In 1969, Frey accepted an offer to join the chemistry department at Ohio State University. He remained there for several years, rising through the ranks to eventually become Professor of Biochemistry and Academic Vice Chair of Chemistry. During his time at Ohio State, Frey started investigating the mechanism of enzyme and coenzyme action in several molecules, including UDP-galactose 4-epimerase, pyruvate dehydrogenase, galactose-1-phosphate uridylyltransferase, UDP-glucose pyrophosphorylase, and adenylate kinase.In 1981, Frey left Ohio State to join the faculty of the Institute for Enzyme Research at the University of Wisconsin, Madison. There he continued to study enzyme mechanisms but also expanded his research to include the structure and function of multienzyme complexes. In the first Journal of Biological Chemistry (JBC) Classic reprinted here, Frey reports the results of his quaternary structural analysis of the pyruvate dehydrogenase complex from Escherichia coli. Using scanning transmission electron microscopy and radial mass analysis, Frey and his colleagues were able to confirm a model in which six dihydrolipoyl dehydrogenase (E₃) dimers are integrated into the six faces of a cubic dihydrolipoyl transacetylase (E₂) core and 12 pyruvate dehydrogenase (E₁) dimers are associated along the 12 edges of the core enzyme.Frey also began to work on lysine 2,3-aminomutase, the enzyme that catalyzed the conversion of l-lysine to l-β-lysine. The reaction involved the interchange of the 2-amino group of lysine with a hydrogen at carbon 3 to form β-lysine and was analogous to adenosylcobalamin-dependent rearrangements in which hydrogen transfer is mediated by the adenosyl moiety of the coenzyme. However, lysine 2,3-aminomutase did not appear to contain adenosylcobalamin, and it wasn''t activated by the coenzyme. To explain this phenomenon, Frey suggested that S-adenosylmethionine was involved in the hydrogen transfer reaction and proposed a mechanism in which the adenosyl-C-5′ moiety of S-adenosylmethionine functioned in the same way as the adenosyl group of adenosylcobalamin in facilitating hydrogen transfer and generating an intermediate free radical that could undergo the amino group migration (1).In the second JBC Classic reprinted here, Frey and his colleagues further tested his proposed mechanism and, by carrying out the lysine 2,3-aminomutase reaction with S-[5′-³H]adenosylmethionine, showed that both hydrogens at adenosyl-C-5′ participate in the hydrogen transfer process. Mass spectral analysis of the β-lysine for monodeutero and dideutero species also demonstrated that the hydrogen transfer is both intramolecular and intermolecular. The results of this paper confirmed that the activation of lysine 2,3-aminomutase involved a transformation of S-adenosylmethionine into a form that promotes the generation of a 5′-adenosyl free radical which abstracts hydrogen from lysine to form 5′-deoxyadenosine as an intermediate.Frey retired in 2008 and is currently an emeritus professor in the biochemistry department at the University of Wisconsin, Madison. In recognition of his contributions to science, he has received many honors and awards including the Alexander von Humboldt Senior Scientist Award (1995), the American Chemical Society Division of Biological Chemistry''s Repligen Award (2000), and the Hilldale Award (2007). Frey is a fellow of the American Association for the Advancement of Science (2003) and the American Academy of Arts and Sciences (2003) and was elected to the National Academy of Sciences (1998). He also served on the editorial board for the Journal Biological Chemistry from 1983 to 1988.     

Contribution of late Professor T. C. Tung to the experimental embryology of Amphioxus

Professor T. C. Tung (Fig. 1) was a prominent experimental embryologist in China. He was born in Jin County, Zhejiang Province, China in 1902. After he obtained his Bachelor's degree from the Department of Biology, Fudan University, Shanghai in 1927, he was appointed as a teaching assistant in that department until he moved to Belgium in 1930. He studied as a graduate student in Professors A. Brachet and A. M. Dalcq's laboratory at the Universite Libre de Bruxelles, Belgium and obtained his Doctor of Science degree there in 1934. During that period, he made two short working visits to the Institute of Marine Biology in France and took one training course at Cambridge University (UK). In 1934, he was invited to return to China as a Full Professor to teach at several Chinese universities, (Shandong University in Qingdao, Shandong Province; the National University in Nanjing; and Fudan University in Shanghai). He spent 1 year at Yale University (USA) between 1948 and 1949 as an invited scientist in a joint research project and finally returned to China in 1949. He was Chairman of the Department of Zoology, Shandong University in Qingdao (1949-1952), Vice-President of Shandong University (1952-1960), Director of the Marine Biological Institute, the Chinese Academy of Sciences (CAS) in Qingdao (1949-1958), Director of the Institute of Oceanology (CAS) in Qingdao (1959-1966), Director of the Institute of Zoology (CAS) in Beijing (1960-1962), member of CAS since 1955, Vice-Chairman of the Biological and Geographical Division of CAS (1955-1958), Chairman of the Biological Division of CAS (1959-1979) and Vice-President of CAS in Beijing (1978-1979). In spite of his administrative duties, he spent most of his life conducting bench work in his laboratories at the Institutes of Oceanology and Zoology, CAS, respectively, until he passed away in March 1979. Professor Tung's main research interest was with classic experimental studies on the determination of the egg axis and symmetry planes of fertilized eggs, early differentiation and organizing substances of egg cytoplasm, induction between embryonic cells and cytoplasm in embryogenesis, immunological studies on nuclear transplanted eggs, and cell fusion etc., in several types of animals. He conducted his experiments on a number of invertebrates (ascidians and Amphioxus) and vertebrates (fish and amphibians) by means of very skillful microsurgical operations and the nuclear transplantation method. Among these topics, his studies on the organization and developmental potency of Amphioxus eggs were unique. His important contribution to this research field involved not only establishing a practical method for collecting and using this rare animal for experimental purposes, but also clarifying controversy about the nature and early development of its eggs. He also provided conclusive evidence to determine its evolutionary position between invertebrates and vertebrates. The present article briefly reviews the main results obtained by Professor Tung and his colleagues on Amphioxus. Although their original articles were written both in Chinese and English, many international readers may not even know those original works because they were only published in scientific journals inside China from the 1950s. Comments and discussion on the experimental results of Amphioxus research by Tung's group and those from other earlier authors are also included.     

Cornelis den hartog: An outstanding aquatic ecologist

A survey is given of the work and life of Cornelis den Hartog up to the date in 1996 at which he retired from his position as a professor at the University of Nijmegen. Cornelis (Kees) den Hartog made important contributions to aquatic ecology in the widest sense,e.g. on brackish water typology, meiofauna (microturbellaria), macroinvertebrates, littoral algae, seagrasses and aquatic macrophytes. He favoured the ecosystem approach in aquatic ecology by studying structure and functioning in an integrated way. He lead 31 students to their doctor's degree (PhD).     

Sergei Winogradsky: a founder of modern microbiology and the first microbial ecologist

Sergei Winogradsky, was born in Russia in 1856 and was to become a founder of modern microbiology. After his Master's degree work on the nutrition and growth physiology of the yeast Mycoderma vini at the University of St. Petersburg, he joined the laboratory of Anton DeBary in Strassburg. There he carried out his studies on the sulfur-oxidizing bacterium Beggiatoa which resulted in his formulation of the theory of chemolithotrophy. He then joined the Swiss Polytechnic Institute in Zurich where he did his monumental work on bacterial nitrification. He isolated the first pure cultures of the nitrifying bacteria and confirmed that they carried out the separate steps of the conversion of ammonia to nitrite and of nitrite to nitrate. This led directly to the concept of the cycles of sulfur and nitrogen in Nature. He returned to Russia and there was the first to isolate a free-living dinitrogen-fixing bacterium. In the flush of success, he retired from science and spent 15?years on his familial estate in the Ukraine. The Russian revolution forced him to flee Russia. He joined the Pasteur Institute in Paris where he spent his remaining 24?years initiating and developing the field of microbial ecology. He died in 1953.     

The role of routine serum testosterone testing: routine hormone analysis is not indicated as an initial screening test in the evaluation of erectile dysfunction

A 60-year-old male physician is self-referred to your office for evaluation of his erectile dysfunction, which has been worsening for 5 years. He reports his erections rarely achieve fullness for penetration, and he is unable to ejaculate. He has tried sildenafil citrate (Viagra(R); Pfizer Inc, New York, NY) with mild success in the past. He has a strong libido and feels healthy. He rarely exercises, but is on his feet most of the day at work. He has been healthy his whole life and never seeks a doctor's attention. He has no other medical problems. His only medication is a baby aspirin once a day. His physical examination, including genitalia, is normal. As part of his initial visit, should his serum testosterone level be checked by his urologist?     

Proteomics data mining

Marc Wilkins completed his undergraduate and doctoral studies at Macquarie University, Sydney, Australia. During his doctoral studies, he defined the concept of the proteome and coined the term. After postdoctoral studies in Geneva, Switzerland, during which he co-edited the first book on proteomics, he returned to Australia, where he cofounded the company Proteome Systems. More recently, Marc took a position as Professor of Systems Biology at the University of New South Wales. He has established and directs the NSW Systems Biology Initiative, and is currently researching the role that protein post-translational modifications play in the regulation of protein-interaction networks.     

Q & A. Carl R. Woese. [interview

Carl R. Woese was born and raised in Syracuse, New York. His undergraduate training was at Amherst College (AB 1950) and graduate work at Yale University (PhD 1953). He is currently the Stanley O. Ikenberry University Professor and Center for Advanced Study Professor of Microbiology at the University of Illinois (Champaign-Urbana), where he has been for the past forty years. He was trained as a biophysicist and molecular biologist. He views himself as a molecular biologist in search of Biology. Consequently, his career has been devoted to using molecular methods to approach evolutionary problems. His most notable accomplishments have been determining the universal phylogenetic tree, through molecular sequence analysis, and the discovery of the Archaea, the so-called ‘third form’ of life. For these he has received numerous awards, including a John D. and Catherine T. MacArthur Award, the Leeuwenhoek Medal 1990 (Netherlands Royal Academy), the Waksman Award (National Academy of Science USA), and the Crafoord Prize (Swedish Royal Academy). At present he works on the evolution of cellular organization.     

Sir Charles Edward Saunders, Dominion cerealist.

Charles Edward Saunders was born in London, Ontario, in 1867. His father, Sir William Saunders, was the first director of the Dominion Experimental Farms (1886-1911). Charles received his B.A. with honours in science from the University of Toronto in 1888 and his Ph.D. in chemistry from Johns Hopkins University in Baltimore, Maryland, in 1891. He attempted a career in music, his first love, from 1893 to 1902. With his father, Charles attended the 1902 International Conference on Plant Breeding and Hybridization in New York, where he learned of Mendel's theories of inheritance and their applicability to plant breeding. When he began work in 1903 in the Division of Cereal Breeding and Experimentation at the Central Experimental Farm in Ottawa, he used the knowledge he had gained at that conference. It was Charles's goal to achieve "fixity" in the varieties that had been bred and released using phenotypic mass selection, prior to his tenure as Cerealist. He selected four heads from the wheat variety Markham and in the winter of 1904 he performed a "chewing test" to select for gluten elasticity and colour. Seeds from two heads were chosen, and seeds from one went on to produce the variety Marquis after extensive yield trials on the Prairies. Marquis was 7 to 10 days earlier than Red Fife, the standard bread wheat of the Prairies. The earliness and tremendous yield of Marquis wheat resulted in the rapid and successful settlement of the Great Plains and countless billions of dollars in revenue to Canada. By 1923, 90% of the spring wheat in Canada and 70% in the USA was Marquis. Charles continued as Dominion Cerealist until his retirement in 1922. He was knighted in 1934, and died in 1937.     

Partial specific volumes and interactions with solvent components of α-globulin fromSesamum indicum L. in urea and guanidine hydrochloride

The interaction of α-globulin with urea/guanidine hydrochloride was investigated by determining the apparent partial specific volumes of the protein in these solvents. The apparent partial specific volumes were determined both under isomolal and isopotential conditions. The preferential interaction parameter with solvent components calculated were 0.08 and 0.1 g of urea and guanidine hydrochloride respectively per g protein. In both the cases the interaction was not preferential with water. The total binding of denaturant to α-globulin was calculated both for urea and guanidine hydrochloride and the correlation between experimentally determined number of mol of denaturant bound per mol of protein and the total number of peptide bonds and aromatic amino acids were found to be in excellent agreement with each other. The changes in volume upon transferring α-globulin from a salt solution to 8 M urea and 6 M guanidine hydrochloride were also calculated. This work was done at the Biochemistry Department, Brandeis University, Waltham, Massachusetts 02254, USA.