Characterization of two cytosolic diacylglycerol kinase forms.
Two forms of rat brain cytosolic diacylglycerol kinase (EC2.7.1.107) were separated by heparin-agarose column chromatography. These forms, designated DGK-I and DGK-II, were not interconvertible as determined by rechromatography. DGK-I and DGK-II had respective molecular masses of 88 and 180 kDa, as measured by Sepharose 6B chromatography. Both forms preferred diacylglycerol over monoacylglycerol and were insensitive to R59022. DGK-II, but not DGK-I, was activated by an activator substance prepared from chicken egg yolk. DGK-II was activated by a rat brain cytosolic activator and was exclusively sensitive to 5'-AMP-mediated inactivation. Further studies revealed that these two forms had the following distinct characteristics: (a) substrate specificity, (b) inhibition by heparin, (c) sensitivity to lysine-containing polyamino acids, and (d) responses to different phospholipids. In general, DGK-II was more responsive to various inhibitors and activators, making it a prime candidate for a regulatable enzyme.
Chen
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Department of Biochemistry, School of Medicine, University of Missouri-Columbia 65212.
Klemm
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Jeng
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I
D000249:Adenosine Monophosphate / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000648:ultrastructure; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000201:enzymology; D019852:Diacylglycerol Kinase; D004789:Enzyme Activation / Q000187:drug effects; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D010743:Phospholipids / Q000494:pharmacology; D010766:Phosphorylation; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D011744:Pyrimidinones / Q000494:pharmacology; D051381:Rats; D013844:Thiazoles / Q000494:pharmacology
D000596:Amino Acids; D007527:Isoenzymes; D010743:Phospholipids; D011744:Pyrimidinones; D013844:Thiazoles; D000249:Adenosine Monophosphate; C047505:R 59022; D010770:Phosphotransferases; D019852:Diacylglycerol Kinase