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61.
P. Mäsiar Eva Mäsiar D.G. Oakley 《Biochemical and biophysical research communications》1973,50(3):914-919
An octapeptide possessing inotropic activity has been isolated from heparinised dog blood plasma. It was found to be composed of seven isoleucine and one glycine residues and an as yet unidentified compound (X). The aminoacid sequence of its peptide chain was elucidated as iLeu. iLeu. iLeu, iLeu. Gly. iLeu. iLeu. The effect of this peculiar peptide compound on the dog heart papillary muscle was found to parallel that of adrenaline calculated on a Mole/Mole basis. The activity of the peptide compound was destroyed by mineral acid hydrolysis. 相似文献
62.
The phosphorylase kinase deficiency (Phk) locus has been located in the mouse X chromosome, the order of genes being centromere-Bn-Phk-Ta-jp. Since the Phk locus of the mouse may be identical to the locus responsible for the X-linked phosphorylase kinase deficiency trait of man, and there may be a high degree of gene-order homology in the X chromosome of all mammals, the location of Phk in the mouse reported here may aid in locating the phosphorylase kinase gene on the X chromosome of man.This research was supported by grants AM 13359 (to F.H.) and AM 14461 (to D.L.C.) from the National Institute of Arthritis and Metabolic Diseases, and by an allocation (to E.M.E.) from NIH General Research Support Grant RR-05545 from the Division of Research Resources to The Jackson Laboratory. F.H. is a recipient of a Research Career Development Award (AM 46 421) of the National Institute of Arthritis and Metabolic Diseases. 相似文献
63.
The adenosine triphosphate inhibition of the pyruvate kinase reaction and its dependence on the total magnesium ion concentration 总被引:4,自引:2,他引:2 下载免费PDF全文
1. The effects of ATP, PP(i) and EDTA on the skeletal-muscle pyruvate kinase reaction at various concentrations of magnesium (where ;magnesium' refers to total Mg(2+), both free and in the form of complexes) were investigated. The reaction rate was determined as the amount of pyruvate formed in a recorded time of incubation. 2. At 44mm-magnesium the K(m) values for ADP and phosphoenolpyruvate were unaltered by the presence of ATP up to 6.8mm in systems buffered with either tris-hydrochloric acid or glycylglycine-sodium hydroxide, but the K(m) values were different in these systems. The K(m) for one substrate was independent of the concentration of the second substrate. 3. At 10mm-magnesium in the tris-hydrochloric acid system ATP inhibited the reaction competitively with respect to ADP and phosphoenolpyruvate. In the glycylglycine-sodium hydroxide system the inhibition appeared to be non-competitive. At 10mm-magnesium the K(m) values were lower than at 44mm-magnesium and dependent on the system used. 4. In the tris-hydrochloric acid system the reaction rate rose with increasing magnesium concentration up to a maximum at a concentration 10-20 times that of ADP. Further increase inhibited the reaction and at 44mm-magnesium the rate was 25-50% of its maximum. This inhibition paralleled that produced by increasing trimethylammonium chloride concentrations and was not due to a specific effect of the Mg(2+) ion. 5. In the presence of 6.8mm-ATP no reaction occurred below 4-6mm-magnesium, and further increase apparently abolished the inhibition as the reaction rate increased and became equal to those obtained in the absence of ATP at 10-25mm-magnesium. Further increase in magnesium concentration gave reaction rates that were slightly higher in the presence of ATP than in its absence. The maximal rate in the presence of ATP was distinctly lower than in its absence. When 6.8mm-PP(i) or 6.8mm-EDTA was present the variations in reaction rate with rising magnesium concentration were similar to that obtained in the presence of ATP below 6-8mm-magnesium but further increase in the magnesium concentration resulted in an increase in the rate up to a maximum comparable with that of the control. The effect of pure chelation was thus a displacement of the reaction maximum to higher magnesium concentrations without changing the maximal rate. When correction had been made for this effect, ATP gave inhibition at 44mm-magnesium that was competitive with respect to ADP (K(i) 2.1x10(-2)m). This degree of inhibition is far less than was reported earlier and its importance for the mechanism of the pyruvate kinase reaction is discussed. 相似文献
64.
Mutant of Escherichia coli with Anomalous Cell Division and Ability to Decrease Episomally and Chromosomally Mediated Resistance to Ampicillin and Several Other Antibiotics 总被引:30,自引:17,他引:13 下载免费PDF全文
In a mutation experiment with a rough, ampicillin-resistant strain, we isolated two smooth mutants which were both sensitive to ampicillin and carried defects in the cell envelope. One of the strains (with the envA gene) is hindered in its completion of septa and forms chains of cells. The envA gene has been mapped to a position between leu and proB, at 2 to 4 min. The envA gene decreased the resistance mediated by both episomal and chromosomal genes for resistance to several antibiotics. During growth the envA mutant was characterized by abnormal ratios between viable count or cell count and optical density. The ratio between viable count and optical density was affected during shift-up and shift-down experiments. When compared to the parent strain, the envA mutant was found to be more resistant to ultraviolet irradiation on plates. Prestarvation for tryptophan had a protective effect against irradiation both on the parent strain and the envA mutant. 相似文献
65.
Zusammenfassung 19 Patienten, die nach einer Nierentransplantation mit Imuran behandelt wurden, wiesen eine erhöhte Anzahl Chromosomenabnormitäten im Vergleich zu 30 gesunden Kontrollpersonen der gleichen Altersklasse auf. Keine signifikant erhöhte Anzahl an Chromosomenabnormitäten fand sich jedoch bei 7 Patienten, die vor und unter der Imuran-behandlung untersucht wurden. Es wird vermutet, daß die Chromosomenabnormitäten bei den 19 mit Imuran behandelten Patienten wahrscheinlich nicht durch Imuran, sondern durch die Urämie entstanden sind.
Summary 19 patients treated with Imuran after a renal transplantation showed a high frequency of chromosome abnormalities, compared with 30 healthy control persons in the same age range. No significantly higher frequency of chromosome abnormalities was, however, found in 7 patients examined before and during treatment with Imuran. It is suggested that the chromosome abnormalities found in the 19 patients treated with Imuran were probably not due to Imuran but to Uremia.相似文献
66.
Total skin collagen is greatly increased in women with hirsuties. This is presumably due to androgen, whether locally produced or circulating. 相似文献
67.
68.
Summary By means of a histochemical method adapted for electron microscopy a cholinesterase in body muscle cells of plaice (Pleuronectes platessa) has been localized to the sarcolemma. The cholinesterase activity disappeared from the sarcolemma after the muscle tissue had been incubated with a bacterial enzyme, which had earlier been shown, by biochemical methods, to be able to liberate this cholinesterase activity from plaice muscle.The provision of live plaices from Kristineberg Zoological Station, Fiskebäckskil, Sweden, is gratefully acknowledged. We are greatly indebted to Dr. Åke Bovallius, FOA, who provided the starting material for the bacterial enzyme. We would like to express our sincere thanks to Prof. Lennart Nicander for valuable discussions and for placing the resources of the Department of Anatomy and Histology, Royal Veterinary College, to our disposal. 相似文献
69.
The Genetic Extent of the Insertion Involved in the Flecked Translocation in the Mouse 总被引:4,自引:1,他引:3 下载免费PDF全文
Eva M. Eicher 《Genetics》1967,55(2):203-212
70.
Eva Janovská 《Folia microbiologica》1964,9(4):256-258
Устойчивость каппа-фага (Serratia marcescens) и его мутанта «С» исследовалась в буферных растворах при pH от 2.5 до 12 с целью подтверждения, или опровержения, возможности их инактивирования в результате кратковременного доведения кислотности основной суспензии в течение приготовления концентрата фага до pH 4. Было установлено, что каппа-фаг и его с-мутант в среде с pH 4 и выше остаются относительно устойчивыми и что в этих пределах pH между обоими фагами нет существенных различий. Однако при низких pH (2,5–3,5) титр обоих фагов вскоре довольно резко падает, причем с-мутантинакмпбпруемся бысмрее, чем каппа-фаг. 相似文献