Abstract
Previous experiments suggesting that tetrahydrofolate binds to serine hydroxymethyltransferase with positive homotropic cooperativity have been reinvestigated. Our results show that the sigmoid-shaped tetrahydrofolate saturation curve, previously obtained by several other investigators, is due to the instability of tetrahydrofolate in the assay solution. Using a different assay method, we have shown that tetrahydrofolate gives a hyperbolic saturation curve with serine hydroxymethyltransferase. We could find no evidence, as suggested by other investigators, that heating the enzyme during purification destroyed its allosteric properties or that NADH binds to the enzyme as an allosteric effector. Evidence is presented that the loss of tetrahydrofolate during the assay period is due to oxidation by dissolved molecular oxygen.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
