The presence of glucosephosphate isomerase, one of the key enzymes in carbohydrate metabolism, was confirmed for the first time in the cell-free extract of Leptospira biflexa.
The glucosephosphate isomerase of L. biflexa was heat-labile and its optimum pH was about 8.5. The enzyme showed an optimal temperature of about 45C but was more stable at 30C. K_m value of the enzyme was 5.6×10^-3M. The activity of the enzyme was inhibited by the inhibitor, 6-phosphogluconate.
From this study, the presence of a metabolic pathway, the phosphogluconate pathway, other than non-oxidative pentose phosphate pathway presented by Baseman and Cox was suggested.