Evidence that tetrahydrofolate does not bind to serine hydroxymethyltransferase with positive homotropic cooperativity.

摘要: Previous experiments suggesting that tetrahydrofolate binds to serine hydroxymethyltransferase with positive homotropic cooperativity have been reinvestigated. Our results show the sigmoid-shaped saturation curve, previously obtained by several other investigators, is due instability of in assay solution. Using a different method, we shown gives hyperbolic curve hydroxymethyltransferase. We could find no evidence, as suggested heating enzyme during purification destroyed its allosteric properties or NADH an effector. Evidence presented loss period oxidation dissolved molecular oxygen.