title: Functional multiplicity of phosphoglucose isomerase from Lactobacillus casei.
abstract: Phosphoglucose isomerase (D-glucose-6-phosphate ketolisomerase, EC 5.3.1.9), purified from Lactobacillus casei, showed multiplicity with respect to electrophoretic mobility, molecular weight, kinetic properties and responses to erythrose 4-phosphate. Among the three forms isolated, one having a dimeric conformation, was specific for glucose 6-phosphate. Erythrose 4-phosphate inhibited this preparation in a sigmoid fashion, while this compound activated the enzyme for isomerization of ribose 5-phosphate. In tetrameric conformation of the similar subunits, the enzyme was more specific for ribose 5-phosphate and the inhibition exerted by erythrose 4-phosphate was hyperbolic. The possible implications of these observations have been discussed.
mesh_terms: D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005952:Glucose-6-Phosphatase / Q000378:metabolism; D005956:Glucose-6-Phosphate Isomerase / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007780:Lacticaseibacillus casei / Q000201:enzymology*; D046911:Macromolecular Substances; D008970:Molecular Weight; D012267:Ribosemonophosphates / Q000378:metabolism; D013403:Sugar Phosphates / Q000494:pharmacology
chemical_list: D046911:Macromolecular Substances; D012267:Ribosemonophosphates; D013403:Sugar Phosphates; C026959:erythrose 4-phosphate; D005952:Glucose-6-Phosphatase; D005956:Glucose-6-Phosphate Isomerase