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161.
162.
O Holian C T Bombeck L M Nyhus 《Biochemical and biophysical research communications》1980,95(2):553-561
The phosphorylation of myelin (basic protein) purified from rabbit brain was markedly stimulated by exogenously added calmodulin in the presence of calcium and inhibited by W-7(N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide), a calmodulin interacting agent, in a dose-dependent fashion. However, exogenously added myelin basic protein free from protein kinase activity could not serve as a substrate of this calmodulin dependent protein kinase, suggesting that this kinase catalyzes the phosphorylation of the enzyme-substrate complex. These results suggest that a calmodulin-dependent protein kinase complex with the substrate (basic protein) is located in the myelin membrane of the central nervous system. 相似文献
163.
164.
J P Burbach J G Loeber J Verhoef E R de Kloet D de Wied 《Biochemical and biophysical research communications》1979,86(4):1296-1303
β-Endorphin (β-LPH 61–91), γ-endorphin (61–77), des-tyrosine-γ-endorphin (62–77), α-endorphin (61–76), and β-LPH 61–69 either labeled with [125I] at the N-terminal 61-tyrosine residue or unlabeled were incubated with a crude synaptosomal plasma membrane fraction of rat brain or in human serum. At different time intervals the release of [125I]-tyrosine or the change in immunoreactivity of the endorphins was determined. The cSPM preparation displayed both high aminopeptidase and endopeptidase activities. In contrast, human serum mainly contained aminopeptidase activity. The data suggest that functional endorphin metabolism may occur at the synaptosomal plasma membrane. These membranes may potentially be involved in the formation of behaviorally active endorphin fragments. 相似文献
165.
166.
Hormonal requirements for the induction of cytochrome P-450 in hepatocytes cultured in a serum-free medium 总被引:11,自引:0,他引:11
J F Sinclair P R Sinclair H L Bonkowsky 《Biochemical and biophysical research communications》1979,86(3):710-717
Drug mediated induction of cytochrome P450 was studied in cultures of hepatocytes that had never been cultured in the presence of serum. Propylisopropylacetamide induced a five-fold increase in cytochrome P450, approximating induced levels, when triiodothyronine and/or dexamethasone were included in the culture medium. Insulin was apparently not required for this induction. Cytochrome P450, free of cytochrome oxidase, could be fully recovered from cell homogenates in a 8700g supernatant, by use of a buffer containing 0.2% Emulgen. 相似文献
167.
The distribution in rat brain of angiotensin converting enzyme (EC3.4.15.1) using hippuryl-His-Leu as substrate was identical to a dipeptidyl carboxypeptidase present in membranes assayed with Met-enkephalin as substrate. Highest activity occurred in pituitary, followed by cerebellum, corpus striatum, midbrain, pons-medulla, hypothalamus, cerebral cortex and spinal cord. The ratio of products His-Leu/Tyr-Gly-Gly was identical for all regions but differed from His-Leu/Tyr. Angiotensin converting enzyme purified by immunoaffinity chromatography gave a Km for hippuryl-His-Leu of 0.5mM and for Met-enkephalin of 0.1 mM. In the presence of the specific inhibitor of angiotensin converting enzyme, SQ 14,225, the Ki value was 10?7M. Present data point to the co-identity of brain angiotensin converting enzyme with the dipeptidyl carboxypeptidase inactivating enkephalin. 相似文献
168.
D Ayusawa K Iwata T Kozu S Ikegami T Seno 《Biochemical and biophysical research communications》1979,91(3):946-954
Mutants that were resistant to aphidicolin were isolated from mutagenized mouse FM3A cells at a frequency of about 10?6. Resistance to aphidicolin in these mutants was not due to an effect on [3H]thymidine incorporation into DNA, DNA synthesis in permeabilized cells, or DNA polymerase α.All the mutants showed a greatly increased dATP pool and decreased ability to incorporate [3H]deoxycytidine into DNA. They also showed cross-resistance to both 1-β-D-arabinofuranosyladenine and 1-β-D-arabinofuranosylcytosine.These results indicate that an enzyme involved in production of dATP or its regulation is altered in these mutants. It is suggested that dATP competes with aphidocolin at its killing site or that dATP reverses the effect of aphidicolin by some unknown mechanism . 相似文献
169.
S Nagao Y Suzuki Y Watanabe Y Nozawa 《Biochemical and biophysical research communications》1979,90(1):261-268
A Ca2+-binding protein (TCBP), which was isolated from , enhanced about 20-fold particulate-bound guanylate cyclase activity in cells in the presence of a low concentration of Ca2+, while the adenylate cyclase activity was not increased. The enhancement was eliminated by ethylene glycol-bis (β-aminoethyl ether)-N,N′-tetraacetic acid. The enzyme activity was not stimulated by rabbit skeletal muscle troponin-C, the Ca2+-binding component of troponin, or other some proteins. In the presence of TCBP, stimulating effect of calcium ion on the enzyme activity was observed within the range of pCa 6.0 to 4.6, and was immediate and reversible. 相似文献
170.