ENZYMATIC ACTIVITY IN TUBULIN PREPARATIONS: CYCLIC‐AMP DEPENDENT PROTEIN KINASEACTIVITYOF BRAIN MICROTUBULE PROTEIN1
作者:
D. Soifer,
期刊:
Journal of Neurochemistry
(WILEY Available online 1975)
卷期:
Volume 24,
issue 1
页码: 21-33
ISSN:0022-3042
年代: 1975
DOI:10.1111/j.1471-4159.1975.tb07623.x
出版商: Blackwell Publishing Ltd
数据来源: WILEY
摘要:
Abstract—Cyclic‐AMP stimulates phosphorylation of Hf1 and Hf2b histone fractions and of protamine by tubulin preparations. Lyophilization of the tubulin removes the requirement for cyclic‐AMP; the kinase is fully active in the absence of cyclic nucleotide. The casein kinase activity of tubulin is independent of cyclic‐AMP. Only cyclic‐IMP can replace cyclic‐AMP at the low concentrations at which the cyclic‐AMP is effective. 5′‐AMP inhibits basal levels of Hf 1 histone phosphorylation. Several attempts have been made to separate the kinase activity from tubulin. Both tubulin and kinase activity are precipitated by vinblastine. Mg2+precipitation of tubulin inactivates the kinase; there is no evidence that the precipitation step removes the kinase from tubulin. Tubulin which has been assembled into microtubules, collected by centrifugation and disassembled, retains its kinase activity. Kinase activity and tubulin co‐elute from DEAE‐cellulose. Taken together, these experiments demonstrate that tubulin, prepared by fractionation with ammonium sulfate followed by elution from DEAE Sephadex with 0‐8 M KC1 and concentration by reprecipitation with ammonium sulfate has a closely associated, cyclic‐AMP dependent protein kinase activity, which may be intrinsic to the tu
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