Abstract
Protein phosphorylation appears to play a central role in regulation of cell processes. We have studied the effects of B 1-320μM on phosphorylation of some purified proteins by different kinases. The proteins in concentrations of 100μg/ml were phosphorylated at 30°C by 10nM concentrations of the kinases with 5μM ATP-32P (148GBq/mM) as phosphate donor. The reactions were stopped after 30s, and phosphorylation was quantitated by scintillation counting of gel pieces after SDS-polyacrylamide gel electrophoresis. B inhibited phosphorylation of the following proteins: Synapsin I by cAMP-dependent kinase (APK) and Ca/calmodulin-dependent kinase II (CaMII); glycogen synthetase by APK and CaMII; histone I by G-kinase; histone IIA by APK, CaMII,and G-kinase (GK); DARPP-32 by APK and GK; and myosin by CaMII; but not G-substrate by GK. IC50 concentrations of B varied from 20-240μM. B may be capable of interfering with a wide range of protein phosphorylation reactions involved in regulation of cell metabolism.
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Hansen, T., Walaas, S. 21 CONCENTRATION-DEPENDENT INHIBITORY EFFECT OF BILIRUBIN (B) ON PHOSPHORYLATION OF SOME PROTEINS. Pediatr Res 24, 264 (1988). https://doi.org/10.1203/00006450-198808000-00047
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DOI: https://doi.org/10.1203/00006450-198808000-00047