title: myo-Inositol-1-phosphate synthase from pine pollen: sulfhydryl involvement at the active site.
abstract: myo-Inositol-1-phosphate synthase [EC 5.5.1.4; 1L-myo-inositol-1-phosphate lyase, (isomerizing)] from Pinus ponderosa pollen has been partially purified and characterized. It has a pH optimum between 7.25 and 7.75. The km for D-glucose 6-phosphate (NAD+ constant at 1 mM) is 0.33 mM. Inhibition by p-chloromercuribenzoate and N-ethylmaleimide, and partial protection against this inhibition by D-glucose 6-phosphate in the presence of NAD+, suggests that there is sulfhydryl group involvement at the substrate binding site.
mesh_terms: D001665:Binding Sites; D002238:Carbohydrate Epimerases / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D007296:Myo-Inositol-1-Phosphate Synthase / Q000378:metabolism*; D011058:Pollen / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D014197:Trees
chemical_list: D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D002238:Carbohydrate Epimerases; D007296:Myo-Inositol-1-Phosphate Synthase