Past investigations in this laboratory have focused on the question of whether the assayed appearance of enzyme activities during the eukaryotic cell cycle of Physarum polycephalum reflect net concurrent syntheses of these respective enzymes. In support of this objective we have established activity patterns for an apparent cyclic AMP-inhibited protein kinase, beta-N-acetyl-glucoaminidase, and uridine 5'diphosphate glucose (UDPG) pyrophosphorylase. Attempts to isolate the kinase with retention of the cyclic AMP-inhibitable property have been unsuccessful and we propose to begin a search for a cyclic AMP-activated protein phosphatase. Occurrence of the latter enzyme could explain earlier observations of decreased phosphorylation of casein in the presence of cyclic AMP by a partially purified protein kinase preparation. Evidence has been discovered for participation of an intraplasmodial protease in the conversion of a 100,000 molecular weight, intraplasmodial glucoaminidase to a 25,000 molecular weight form which is extraplasmodial. This conversion in developmentally controlled and occurs rapidly on initiation of differentiation of plasmodia to spherules. Comparative investigations have been proposed between the isolated extraplasmodial enzyme and that form generated by protease- treatment of purified intraplasmodial glucoaminidase in vitro. UDPG pyrophosphorylase will be isolated by affinity chromatography on an agarose-UDP column and its labeling pattern will be investigated during spherulation. We have isolated in 50 mg-quantities, a previously unreported polyamine from Physarum and the urine of cancer patients, and have established it chemical formula. Structural determination of this amine will be completed followed by confirmation through chemical synthesis.
NIH ExPorter
NIH ExPorter