Dual effect of arachidonic acid on protein kinase C isoenzymes isolated from rabbit thymus cells.
Type II and type III isoenzymes of protein kinase C isolated from rabbit thymus cells were activated at relatively low concentrations but were inhibited at higher concentrations of arachidonic acid. Activation by cis-unsaturated fatty acids required Ca2+; the maximal activity was approached at about 10(-6) M Ca2+ concentration. The kinetics of activation and inhibition by arachidonic acid depended strongly on the nature of the substrate (synthetic oligopeptide or H1 histone), on the concentration of the protein substrate and on the stage of purification of the isoenzyme preparation investigated. Activation seemed to be favoured at high protein concentrations.
Buday
L
L
1st Institute of Biochemistry, Semmelweis University Medical School, Budapest, Hungary.
Faragó
A
A
D000595:Amino Acid Sequence; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004789:Enzyme Activation; D006657:Histones / Q000378:metabolism; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D013379:Substrate Specificity; D013950:Thymus Gland / Q000201:enzymology*
D001095:Arachidonic Acids; D006657:Histones; D007527:Isoenzymes; D009842:Oligopeptides; D016718:Arachidonic Acid; D011493:Protein Kinase C; D002118:Calcium