Phosphorylation of Casein
ROLE OF THE GOLGI APPARATUS
- From the Eastern Regional Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Philadelphia, Pennsylvania 19118
Abstract
A protein kinase that catalyzes the phosphorylation of dephosphorylated αs1-casein by ATP has been found in the Golgi apparatus of lactating rat mammary gland. This enzyme has more than 10 times the specific activity of the protein kinases in other subcellular fractions. When native αs1-casein is used as the substrate, the rate of phosphorus incorporation decreases by 77%. This suggests that phosphorylation of casein may occur in the Golgi apparatus following biosynthesis of the polypeptide chain.
Footnotes
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- Received September 28, 1972.
- © 1972, by the American Society of Biological Chemists, Inc.
