共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary The effect of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), alone and in combination, on diffusion artifacts in histochemical incubations has been investigated using LDH as model enzyme. By measuring the amount of formazan in the medium at the end of the incubation it has been shown that both substances, but especially PVA, are effective in limiting diffusion. The significance of this is discussed in general as well as in relation to other procedures used to reduce diffusion artifacts.The Following Abbreviations are used in the Article NAD
-Nicotinamide Adenine Dinucleotide
- NADH
-Nicotinamide Adenine Dinucleotide, Reduced form
- PVA
Polyvinyl alcohol
- PVP
Polyvinyl pyrrolidone
- PMS
Phenazine methosulfate
- tris
tris (hydroxymethyl)-aminomethan
- Nitro-BT
Nitro Blue Tetrazolium
- LDH
Lactic dehydrogenase 相似文献
2.
Summary The present study deals with the histochemical demonstration of 17-estradiol dehydrogenase in human term placenta using the polyvinyl alcohol method to reduce diffusion artefacts. Incubations took place with both NAD+ and NADP+ as coenzymes and at different pH values of the incubation medium. The NAD+ linked enzyme reaction showed a greater activity than the NADP+ linked, both in the trophoblast as well as in connective tissue. There were differences in staining intensity at the different pH values, and strongest reaction was observed using glycine-NaOH buffer pH 10 in the incubation medium. Owing to a non-enzymatically reduction of nitro blue tetrazolium by reduced NAD+, the demonstration of 17-estradiol dehydrogenase is independent of diaphorase at this high pH. The findings are discussed in relation to data about nothing dehydrogenase and biochemically determined pH optima for the enzymatic reactions dealt with in this work.The following Abbreviations are used in this Article NAD+
-nicotinamide adenine dinucleotide
- NADP+
nicotinamide adenine dinucleotide phosphate
- NBT
nitro blue tetrazolium
- PVA
polyvinyl alcohol
- tris
tris (hydroxymethyl)-aminomethane
- 17-OH-SDH
17-OH-steroid-dehydrogenase
Supported by The Norwegian Research Council for Science and the Humanities. Skilful assistance of Mrs. E. Alvestad, Mrs. Aa. Flatnes and Mrs. F. Sørensen is greatfully acknowledged. 相似文献
3.
The 12.5-kb EcoRI restriction fragment PP1 of Alcaligenes eutrophus strain H16, which encodes for -ketothiolase, NADP-dependent acetoacetyl-CoA reductase and poly(-hydroxybutyric acid)-synthase was mobilized to six different species of the genus Pseudomonas belonging to the rRNA homology group I. Pseudomonas aeruginosa, P. fluorescens, P. putida, P. oleovorans, P. stutzeri and P. syringae, which are unable to synthesize and accumulate poly(-hydroxybutyric acid), PHB, were employed as recipients. Whereas the A. eutrophus PHB-synthetic enzymes were only marginally expressed in P. stutzeri, they were readily expressed in the other species. For example, the specific activity of PHB-synthase was 1.8 U/g protein in transconjugants of P. stutzeri but was between 21 and 77 U/mg protein in transconjugants of the other species. All recombinant strains harboring plasmid pVK101::PP1 except those of P. stutzeri accumulated PHB; the PHB content of the cells grown on gluconate under nitrogen limitation varied between 8 and 24.3% of the cellular dry mass.Abbreviations PHB
poly(-hydroxybutyric acid)
- PHA
poly(hydroxyalkanoic acid) 相似文献
4.
Mycelial and yeast forms of P. brasiliensis were tested for several glucohydrolases. In addition to high levels of -blucanases, low amounts of -glucanase, chitinase and maltase were found. Tests for invertase, amylase and lactase were negative. The levels of -1,3-glucanase were higher in the mycelial form. The shift to the mycelial phase correlated with an increase in the levels of -1,3-glucanase. The enzyme was present in the cytoplasm, cell wall and culture medium. The extracellular enzyme was purified 42 fold by ammonium sulphate precipitation and gel filtration. Maximal activity was obtained at 60°C and pH of 5.0 acetate buffer or pH 6.0 (phosphate buffer). Its K
m was 0.205 mg/ml. The cell wall-bound enzyme showed a higher temperature optimum. Optimum pH and K
m were also slightly different. Following treatment of the cell walls with chitinase, -1,3-glucanase was released into the medium. 相似文献
5.
The -glucan synthetase activity of the fungus Saprolegnia monoica was assayed by supplying UDP-glucose to membrane fractions of mycelial homogenate. The analysis of glucan products by hydrolysis with various -glucanases and by chromatography show that both -1-3- and -1-4-linkages are formed at high substrate concentrations. In the absence of MgCl2, -1-3-linked glucans are mainly produced. By increasing MgCl2 concentrations the total synthesis activity and -1-3-linkages production are reduced. At low substrate concentrations in the presence of MgCl2, -1-4-linked glucans are the only polysaccharide synthesized. Electron microscopy of radioactive products, synthesized by original membrane fractions or by membrane fractions isolated from continuous sucrose density gradients, shows microfibrils when the assays are conducted at high substrate concentrations in the absence of MgCl2.Abbreviations G.S. I
glucan synthetase I
- G.S. II
glucan synthetase II
- Dol. P
dolichol phosphate 相似文献
6.
The effect of estradiol, hydrocortisone and progesterone on 3,20-and 3,17-hydroxysteroid dehydrogenase (HSD) in mutants of Streptomyces hydrogenans was compared to the steroid response of the wild type. Mutants were defective in arginine biosynthesis and/or aerial mycelial formation and lacked both enzymes or only 17-HSD. Some 17-HSD mutants had lost the ability to be induced by estradiol, by progesterone or by both. Some 20-HSD mutants had lost the ability to be induced by hydrocortisone, by progesterone or by both. Non-inducibility of 17-and 20-HSD by progesterone was not co-ordinate. An additional study of the growth phase-dependent enzyme activity of the wild type after induction with estradiol, hydrocortisone and progesterone was performed.Non-standard abbreviations 17-HSD
3,17-Hydroxysteroid dehydrogenase (EC 1.1.1.51)
- 20-HSD
3,20-hydroxysteroid dehydrogenase (EC 1.1.1.53)
- AO
acridine orange
- EBr
ethidium bromide
- EMS
ethyl methanesulfonate
- MNNG
N-methyl-N-nitro-N-nitrosoguanidine 相似文献
7.
Yoshiharu Matahira Atsushi Tashiro Toshinari Sato Hirokazu Kawagishi Taichi Usui 《Glycoconjugate journal》1995,12(5):664-671
N-acetylhexosaminidase fromNocardia orientalis catalysed the synthesis of lacto-N-triose II glycoside (-d-GlcNAc-(1-3)--d-Gal-(1-4)--d-Glc-OMe,3) with its isomers -d-GlcNAc-(1-6)--d-Gal-(1-4)--d-Glc-OMe (4) and -d-Gal-(1-4)-[-d-GlcNAc-(1-6)]--d-Glc-OMe (5) throughN-acetylglucosaminyl transfer fromN,N-diacetylchitobiose (GlcNAc2) to methyl -lactoside. The enzyme formed the mixture of trisac-charides3, 4 and5 in 17% overall yield based on GlcNAc2, in a ratio of 20:21:59. Withp-nitrophenyl -lactoside as an acceptor, the enzyme also producedp-nitrophenyl -lacto-N-trioside II (-d-GlcNAc-(1-3)--d-Gal-(1-4)--d-Glc-OC6H4NO2-p,6) with its isomers -d-GlcNAc-(1-6)--d-Gal-(1-4)--d-Glc-OC6H4NO2-p (7) and -d-Gal-(1-4)-[-d-GlcNAc-(1-6)]--d-Glc-OC6H4NO2-p (8). In this case, when an inclusion complex ofp-nitrophenyl lactoside acceptor with -cyclodextrin was used, the regioselectivity of glycosidase-catalysed formation of trisaccharide glycoside was substantially changed. It resulted not only in a significant increase of the overall yield of transfer products, but also in the proportion of the desired compound6.Abbreviations GlcNAc2
2-acetamido-2-deoxy--d-glucopyranosyl-(1-4)-2-acetamido-2-deoxy-d-glucose
- NAHase
N-acetylhexosaminidase
- -CD
-cyclodextrin 相似文献
8.
A vacuolar type -d-fructofuranosidase (Osfruct3) was cloned from etiolated rice seedlings cDNA library. It encodes an open reading frame of 688 residues. The deduced amino acid sequence had 58% identity to the vacuolar type -d-fructofuranosidase of maize (Ivr1). Osfruct3 exists as a single copy per genome. Northern analyses showed that Osfruct3 undergoes organ-specific expression and is involved in the adjustment of plant responses to environmental signals and metabolizable sugars. Osfruct3 was also heterologously expressed in Pichia pastoris. The recombinant proteins were confirmed to be a vacuolar type -d-fructofuranosidase. 相似文献
9.
The acrylamide quenching of the intrinsic tryptophanyl fluorescence of normal and sickle apohemoglobins has been studied in 0.05 M potassium phosphate buffer,pH 7.5, at 5°C over a protein concentration range from 1 to 50M. Analysis of quenching dynamics revealed a strong dependence on acrylamide concentration for the intrinsic fluorescence of both normal and sickle apohemoglobins, suggesting that one tryptophanyl residue [presumably that at position 37(C3)], was more accessible to collisional quencher than the other tryptophanyl residue [15(A12)]. Additional studies, which altered viscosity and subunit assembly experimental parameters, supported the assignment of residue 37 as the more dynamically accessible residue. Finally, the quenching data were also found to be dependent on protein concentration, implying that this difference in the mobility between the two residues is a sensitive probe of self-aggregation. Extrapolated dynamic quenching constants at low concentration of acrylamide were used to estimate the dimer-monomer equilibrium dissociation constants of normal and sickle apohemoglobins, and were found to be 5.6 and 2.4M, respectively, thus demonstrating distinct self-association properties of
A and
S apohemoglobins. 相似文献
10.
We report here the in vivo production of type 2 fucosylated-N-acetyllactosamine oligosaccharides in Escherichia coli. Lacto-N-neofucopentaose Gal1-4GlcNAc1-3Gal1-4(Fuc1-3)Glc, lacto-N-neodifucohexaose Gal1-4(Fuc1-3)Glc-NAc1-3Gal1-4(Fuc1-3)Glc, and lacto-N-neodifucooctaose Gal1-4GlcNAc1-3Gal1-4(Fuc1-3)GlcNAc1-3Gal1-4(Fuc1-3)Glc were produced from lactose added in the culture medium. Two of them carry the Lewis X human antigen. High cell density cultivation allowed obtaining several grams of fucosylated oligosaccharides per liter of culture. The fucosylation reaction was catalyzed by an -1,3 fucosyltransferase of Helicobacter pylori overexpressed in E. coli with the genes lgtAB of N. meningitidis. The strain was genetically engineered in order to provide GDP-fucose to the system, by genomic inactivation of gene wcaJ involved in colanic acid synthesis and overexpression of RcsA, positive regulator of the colanic acid operon.To prevent fucosylation at the glucosyl residue, lactulose Gal1-4Fru was assayed in replacement of lactose. Lactulose-derived oligosaccharides carrying fucose were synthesized and characterized. Fucosylation of the fructosyl residue was observed, indicating a poor acceptor specificity of the fucosyltransferase of H. pylori. 相似文献
11.
The structural requirements for the interaction of asparagine-linked oligosaccharide moieties of glycoproteins withErythrina variegata agglutinin (EVA) were investigated by means of affinity chromatography on an EVA-Sepharose column. Some of the branched poly-N-acetyllactosamine-type oligosaccharides obtained from human erythrocyte band 3 glycoprotein were found to show high affinity to EVA-Sepharose, whereas complex-type oligosaccharides were shown to have low affinity. Hybrid type, oligomannose-type and unbranched poly-N-acetyllactosamine-type oligosaccharides bound very little or not at all to EVA-Sepharose. To further study the carbohydrate-binding specificity of this lectin, we investigated the interaction of immobilized EVA and oligosaccharide fragments obtained through partial hydrolysis from branched poly-N-acetyllactosamine-type oligosaccharides. Branched poly-N-acetyllactosamine-type oligosaccharides were subjected to limited hydrolysis with 0.1% trifluoroacetic acid at 100°C for 40 min and then separated on an amino-bonded silica column. One of pentasaccharides thus prepared strongly bound to the EVA-Sepharose column. Structural analysis of this pentasaccharide showed that the Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal sugar sequence, which is an l-antigen determinant, was essential for the high affinity binding of the oligosaccharides to the EVA-Sepharose column.Abbreviations EVA
Erythrina variegata agglutinin
- WGA
wheat germ agglutinin
- STA
potato lectin
- LEA
tomato lectin
- DSA
Datura stramonium agglutinin
- PBS
0.01 M sodium phosphate buffer, pH 7.3, containing 0.15 M NaCl
- Galol
galactitol 相似文献
12.
Hiroyuki Narushima Toshio Omori Yasuji Minoda 《Applied microbiology and biotechnology》1982,16(4):174-178
Summary A bacterium capable of utilizing -pinene as a sole carbon and energy source was isolated from soil. This strain, named strain S201-1, which was identified as Pseudomonas maltophilia on the basis of its taxonomical properties, accumulated limonene, borneol, camphor, perillic acid, and 2-(4-methyl-3-cyclohexenylidene) propionic acid from -pinene in the culture broth. It was demonstrated that -pinene, -pinene, borneol, camphor, and a number of p-menthane derivatives were oxidized by this strain. Relations between the protonation of -pinene and the formation of the products by the microbe are discussed. 相似文献
13.
Summary Acid phosphatase was studied by means of electron microscope cytochemistry in glutaraldehyde-fixed myxamoebae of Dictyostelium discoideum grown on dead bacteria. The enzyme activity was localized to the digestive vacuoles in vegetative as well as in aggregating cells. Biochemical experiments showed that the enzyme was not inactivated by fixation in 2% purified glutaraldehyde.Abbreviations used NPP
p-nitrophenyl phosphate
- NP
p-nitrophenol
- GP
-glycerophosphate
- glc-6-P
glucose-6-phosphate
- Pi
orthophosphate 相似文献
14.
Summary A biolistic particle gun was used to deliver genetic material into intact yam cells. Cultured suspension cells of D. alata were bombarded with microprojectiles coated with pBI221.2 DNA and histochemical assays were carried out to show transient GUS expression in bombarded cells. Stably transformed D. alata cells were recovered from cultured cells after bombardment with microprojectiles coated with pRT99gus harbouring both the nptII and uidA genes. Bombarded cells were selected on a medium containing geneticin (G418). Two months after bombardment, calli resistant to G418 were assayed for GUS expression. There was a 100% correlation between resistance to G418 and GUS expression. From these calli, four cell lines were established and GUS activity in each line was determined fluorometrically. The use of a specific GUS inhibitor showed that the GUS activity was due to the introduced uidA gene rather than to any intrinsic GUS-like activity originating from the plant. Incorporation of the introduced DNA into the plant genomic DNA was confirmed by Southern analysis.Abbreviations GUS
-glucuronidase
- MU
4-Methylumbelliferone
- MUG
4-Methylumbelliferyl--D-glucuronide
- PVP
Polyvinylpyrrolidone
- SDS
Sodium dodecyl sulphate
- TAE
Tris-acetate-EDTA buffer
- X-Gluc
5-Bromo-4-chloro-3-indolyl--D-glucuronide 相似文献
15.
Boel Lanne Jeana Cîopraga Jörgen Bergström Cecilia Motas Karl-Anders Karlsson 《Glycoconjugate journal》1994,11(4):292-298
The carbohydrate-binding specificity ofPseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal3Gal- or Gal4Gal-structures.Abbreviations PA-I
Pseudomonas aeruginosa lectin I
- Cer
ceramide
- lactosylceramide
Gal4GlcCer
- iso globotriaosylcerami
Gal3Gal4GlcCer
- globotriaosylceramide
Gal4Gal4GlcCer
- globoside or globotetraosylceramide
GalNAc3Gal4Gal4GlcCer
- Forssman glycolipid
GalNAc3GalNAc3Gal4Gal4GlcCer
- P1 glycolipid
Gal4Gal4GlcNAc3Gal4GlcCer
- lactoneotetraosylceramide
Gal4GlcNAc3Gal4GlcCer
- B5 glycolipid
Gal3Gal4GlcNAc3Gal4GlcCer
- gangliotetraosylceramide
Gal3GalNAc4Gal4GlcCer
- GM1
Gal3GalNAc4(NeuAc3)Gal4GlcCer
- RBC
red blood cells
- BSA
bovine serum albumin
- PBS
phosphate-buffered saline
- SDS
sodium dodecyl sulfate
- TLC
thin-layer chromatography
- HPLC
high pressure liquid chromatography
- MS
mass spectrometry
- FAB
fast-atom bombardment
- EI
electron impact 相似文献
16.
Jiri Svejcar Sarah Ehrlich-Rogozinski Dorothea Riedel Johannes Müthing Nathan Sharon 《Glycoconjugate journal》1993,10(3):247-250
The mammalian placenta is a unique organ for the study of developmental changes. Placentas of laboratory animals such as the mouse allow for the determination of the exact stage of pregnancy, which cannot be achieved with human placenta. In this study, neutral glycosphingolipids were isolated from mouse (inbred strain C57BL/6) placentas, from day 10 to day 18 of gestation, and were separated by high performance thin layer chromatography. Densitometric measurements after orcinol staining showed, at day 10 of gestation, the presence of mono-, tetra-, tri- and dihexosylceramide in decreasing quantities, as well as four unidentified spots. On day 12, the glycosphingolipid composition changed with the disappearance of the unidentified spots and the appearance of an orcinol positive spot migrating similarly to the Forssman antigen; no further changes occurred between days 12 and 18 of gestation. The identity of the Forssman-like glycosphingolipid with the Forssman antigen was established by binding of125I labelledHelix pomatia agglutinin (-GalNAc specific) to glycosphingolipids separated on high performance thin layer chromatography plates, and by the reaction of the isolated glycosphingolipid with a monoclonal anti-Forssman antibody. The appearance of the Forssman antigen at day 12 of gestation coincided with the day of final maturation of the mouse placenta and subsequent cessation of growth, suggesting a possible role of the glycosphingolipid during embryonic development.Abbreviations asialo-GM1
Gal 3GalNAc4Gal4Glc1Cer
- BCIP
5-bromo-4-chloro-3-indolylphosphate
- DHC
lactosylceramide, Gal4Glc1Cer
- Forssman antigen
GalNAc3GalNAc3Gal4Gal4Glc1Cer
- globoside
GalNAc3Gal4Gal4Glc1Cer
- GSL
glycosphingolipids
- HPA
Helix pomatia agglutinin
- HPTLC
high performance thin layer chromatography
- MHC
galactosylceramide, Gal1Cer
- MHC
glucosylceramide, Glc1Cer
- PBS
phosphate-buffered saline
- PNA
peanut agglutinin
- PVP
poly(vinylpyrrolidone), mol. wt 40 000
- SBA
soybean agglutinin
- THC
trihexosylceramide, Gal4Gal4Glc1Cer.
To whom correspondence should be addressed. 相似文献
17.
Fred A. Exterkate Gerrie J. C. M. de Veer 《Applied microbiology and biotechnology》1987,25(5):471-475
Summary Initiation of growth and the growth rate of Streptococcus cremoris HP in a complete synthetic medium supplemented with an enzymatic digest of casein appeared to be inhibited by (di)hydrogen phosphate. The inhibitory effect of the inorganic phosphate fraction was counteracted by -glycerophosphate.Growth experiments involving different caseins or combinations of caseins as the only source of nitrogen (and essential amino acids) were performed in an adapted medium in which optimal growth was expected to depend only on the type of nitrogen source. Maximal growth occurred on a combination of -casein and a relatively low concentration of . It approximated the growth on milk added to the medium. These results and those showing the capacity of the organism to grow on milk-derived fractions suggest that in milk it is mainly the soluble (-) casein fraction together with the easily accessible hydrophilic part of micellar , which maintain optimal growth. 相似文献
18.
Margaret R. Kasschau Christopher M. Skisak J. Philip Cook W. Ronald Mills 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1984,154(2):181-186
Summary During high salinity stress, -alanine accumulates to high levels in the sea anemone,Bunodosoma cavernata. Following a salinity increase from 26 to 40 -alanine increased 28-fold from 1.5 to 41.9 moles/g dry weight. Both whole animal studies and experiments with cell free homogenates indicate that under high salinity conditions an increase in the rate of -alanine synthesis from aspartic acid as well as a decrease in the rate of -alanine oxidation are responsible for the observed accumulation of -alanine. The rate of aspartic acid decarboxylation to -alanine is about 3 times greater in anemones acclimated to 40 than for those in normal salinity water (26). -alanine oxidation to CO2 and acetyl-CoA proceeds 2.5 to 3 times slower in high salinity adaptedB. cavernata than in those acclimated to normal salinity. There is always a rapid degradation of uracil to -alanine, but this does not change with salinity.Abbreviations
CASF
cold acid soluble fraction
-
FAA
free amino acids
-
MES
2(N-morpholino) ethane sulfonic acid
-
NPS
ninhydrin positive substances
-
PCA
perchloric acid
-
TCA
trichloroacetic acid 相似文献
19.
Ritva Niemelä Jari Natunen Elina Brotherus Annamari Saarikangas Ossi Renkonen 《Glycoconjugate journal》1995,12(1):36-44
A partially purified preparation of 1,3-fucosyltransferase(s) from human milk was used to [14C]fucosylate oligosac-charides containing Gal1-4GlcNAc units. Substitution ofN-acetyllactosamine at position 3 with a -linkedN-acetylglucosamine enhanced the reactivity of the acceptor, whereas similar substitution at position 6 was inhibitory. Thus, the trisaccharide GlcNAcl-6Gal1-4GlcNAc (5), the branched tetrasaccharide GlcNAc1-3(GlcNAc1-6)Gal1-4GlcNAc (11) and the triply branched decasaccharide GlcNAc1-3(GlcNAc1-6)Gall-4GlcNAc1-3[GlcNAc1-3(GlcNAc1-6)Gal1-4GlcNAc1-6]Gal1-4GlcNAc (26) gave remarkably poor yields of 1,3-fucosylated products in comparison to GlcNAc1-3Gal1-4GlcNAc (3). 1,4-Galactosyl derivatives of5 and11, however, gave good yields of 1,3-fucosylated products, but the fucosylation was restricted to the distalN-acetyllactosamine units of Gal1-4GlcNAc1-6Gal1-4GlcNAc (16), Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal1-4GlcNAc (18) and also in Gal1-3Gal1-4GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal1-4GlcNAc (22). Immobilized wheat germ agglutinin (WGA), possessing high affinity for16 [1], revealed no affinity for the fucosylated derivative Gal1-4(Fuc1-3)GlcNAc1-6Gal1-4GlcNAc (17). The isomeric heptasaccharides Gal1-4(Fuc1-3)GlcNAc1-3(Gal1-4GlcNAc1-6)Gal1-4GlcNAc (19) and Gal1-4GlcNAc1-3[Gal1-4(Fuc1-3)GlcNAc1-6]Gal1-4GlcNAc (20) were readily separated from each other on WGA-agarose, and so were the isomeric nonasaccharides Gal1-3Gal1-4(Fuc1-3)GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal1-4GlcNAc (23) and Gal1-3Gal1-4GlcNAc1-3[Gal1-3Gal1-4(Fuc1-3)GlcNAc1-6]Gal1-4GlcNAc (24). 相似文献
20.
A. H. Baillie K. C. Calman M. M. Ferguson D. McK. Hart 《Histochemistry and cell biology》1965,5(5):384-395
Summary Mouse, rat, hamster, guinea pig and sheep kidneys and foetal human, adult male and female human, mouse, rat, hamster and guinea pig livers were examined for hydroxysteroid dehydrogenase activity.3-Hydroxysteroids were utilised by all tissues, including neonatal mouse kidney, but the 5-configuration was a more suitable substrate than the corresponding 5-steroid. Both N.A.D. and N.A.D.P. were suitable cofactors.Only trace 3-hydroxysteroid dehydrogenase activity was demonstrable in renal tissue, however liver possessed a higher level of activity and lanosterol, a precurser of cholesterol, was an especially suitable substrate possibly indicating that the liver is capable of synthesising cholesterol.6-Hydroxyprogesterone was poorly utilized by renal and hepatic tissue and N.A.D. was found to be the only cofactor suitable for this reaction. All the tissues, possessed 11-hydroxysteroid dehydrogenase activity. In the kidney, this enzyme occurred in the collecting tubules. It was further noted that in mouse kidney 11-hydroxysteroid dehydrogenase was absent at birth but appeared within the first fourteen days. Activity with 11-hydroxysteroids was observed to be more prominent in the liver of male animals and this pattern was also found with 3-, 3-, 16- and 16-hydroxysteroids, all of which are confirmed by previous biochemical findings.Renal tissue was not capable of utilizing the 16-hydroxysteroid in contrast to liver which could use this substrate fairly well. 16- and 17-hydroxysteroid dehydrogenases were demonstrable in the livers of all species and in all kidneys. The 20-hydroxysteroid was only poorly utilized by hepatic tissue and not at all by renal tissue.Slight activity was demonstrable with 5- and 5-androstans as substrates in liver and the diformazan deposition was presumably due to the action of a steroid reductase. 相似文献