title: Serine transhydroxymethylase. Equilibrium binding of folate analogs as active site probes.
abstract: Formation of a quinoid-like structure within the glycyl-pyridoxal phosphate moiety of serine transhydroxymethylase (5,10-methylenetetrahydrofolate: glycine hydroxymethyltransferase, EC 2.1.2.1) is dependent upon the dissociation of the 2-S hydrogen of glycine which in turn requires the presence of tetrahydrofolate or analogs thereof. Equilibrium binding studies with the series folate, dihydrofolate, and tetrahydrofolate showed that reduction of the pteridine ring enhances both quinoid formation and binding. A 5,8-deazafolate series showed that modifications in the 4 position, 10 position and the glutamyl position yield interrelated alterations of quinoid formation which could not be correlated with binding.
mesh_terms: D001665:Binding Sites; D005492:Folic Acid / Q000031:analogs & derivatives*; D012696:Glycine Hydroxymethyltransferase / Q000378:metabolism; D011485:Protein Binding; D013329:Structure-Activity Relationship; D014166:Transferases / Q000378:metabolism
chemical_list: D005492:Folic Acid; D014166:Transferases; D012696:Glycine Hydroxymethyltransferase