In:
Biochemical Journal, Portland Press Ltd., Vol. 132, No. 3 ( 1973-03-15), p. 603-608
Abstract:
The synthesis rates of total heart protein and of sarcoplasmic and myofibrillar protein fractions have been determined by perfusion of isolated rat hearts with [14C]tyrosine at constant specific radioactivity. In hearts perfused without insulin, both myofibrillar and sarcoplasmic proteins were synthesized at a fractional rate of 10–11% per day. This corresponds to a half-life for synthesis of about 7 days. The effect of added insulin was to increase the rate of heart-protein synthesis to a half-life of 3–4 days. With hearts perfused via the left atrium and performing external work, there was a rise in the specific radioactivity of intracellular free tyrosine, and the half-life for synthesis of proteins was 3–4 days. The extent of labelling of individual myofibrillar proteins was estimated after polyacrylamide-gel electrophoresis of solubilized myofibrils in the presence of sodium dodecyl sulphate. No particular protein showed an unusually high or low specific radioactivity after labelling in perfusion. Insulin caused a general increase in labelling of all the proteins analysed.
Type of Medium:
Online Resource
ISSN:
0306-3283
Language:
English
Publisher:
Portland Press Ltd.
Publication Date:
1973
detail.hit.zdb_id:
1473095-9
