A nonspecific inhibitory effect of tRNA on the activity of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase from Saccharomyces cerevisiae.
The inhibitory effect of tRNA on yeast 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase (EC 4.1.2.15) has been reinvestigated. From earlier studies the inhibition by tRNAPhe appeared to be quite specific. This study shows that tRNAPhe is indeed a potent inhibitor but so is unfractionated tRNA, as well as ribosomal RNA and heparin. Complete digestion to mononucleotides relieves the inhibition. Since the enzyme requires a metal ion (Co2+) we suggest that the RNA and heparin are inhibitory by virtue of their capacity to chelate the Co2+.
D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000446:Aldehyde-Lyases / Q000037:antagonists & inhibitors*; D003035:Cobalt / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009532:Nickel / Q000494:pharmacology; D010649:Phenylalanine / Q000494:pharmacology; D012343:RNA, Transfer / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology*
D003035:Cobalt; D008345:Manganese; D010649:Phenylalanine; D009532:Nickel; D012343:RNA, Transfer; D010723:3-Deoxy-7-Phosphoheptulonate Synthase; D000446:Aldehyde-Lyases; D008274:Magnesium