标题：Substrate proteins for calmodulin-sensitive and phospholipid-sensitive Ca2+-dependent protein kinases in heart, and inhibition of their phosphorylation by palmitoylcarnitine
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：8
页码：4813-4817
DOI：10.1073/pnas.78.8.4813
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：At least two substrate proteins for phospholipid-sensitive Ca2+-dependent protein kinase and at least six substrates for calmodulin-sensitive Ca2+-dependent protein kinase were identified in the cytosol of the guinea pig heart. In the particulate subfractions enriched in nuclei, mitochondria, microsome, or plasma membrane, no substrates for the phospholipid-sensitive enzyme were demonstrated but at least four substrates for the calmodulin-sensitive enzyme were identified. The present studies suggest that phospholipid, acting independently of calmodulin, is likely to be involved in the regulation of Ca2+-dependent protein phosphorylation in the heart. Phosphorylation of endogenous substrates for the two enzyme systems was effectively inhibited by palmitoylcarnitine. When histone was used as exogenous substrate, the carnitine ester inhibited the cardiac phospholipid-sensitive Ca2+-dependent protein kinase but not the cardiac cyclic AMP-dependent and cyclic GMP-dependent protein kinases. It is suggested that inhibition of the Ca2+-dependent phosphorylation of cardiac proteins, regulated by either phospholipid or calmodulin, is probably related in part to the great increase in this fatty acid metabolic intermediate in the ischemic heart.
