STIMULATION OF GLUCOSE OXIDATION IN EXTRACTS OF BACTERIAL SPORES BY DIPICOLINIC ACID

Abstract

The addition of pure dipicolinic acid to cell-free extracts of spores of Bacillus cereus var. terminalis results in an increase in oxygen uptake resulting from the oxidation of glucose. This stimulation, in undialyzed extracts, is proportional to the amount of DPA added up to 3 rag. per ml. of extract.Dialysis of the extract against phosphate buffer, Tris buffer, and glycyl glycine buffer results in a decrease in glucose oxidation as compared to non-dialyzed extracts. Replacement of the DPA loss during dialysis increases the oxygen uptake to approximately the same level as obtained with non-dialyzed extracts without added DPA. The addition of Versene (EDTA) rather than DPA to dialyzed and non-dialyzed extracts also stimulates the oxidation of glucose.Calcium reduces the enzymatic activity by approximately one-half in dialyzed extracts. This inhibition is completely reversed by replacing the DPA loss during dialysis.The possibility is discussed that one of the functions of DPA in the spores of aerobic bacilli is the removal, by chelation, of some inhibitory metallic ion, probably calcium.