This protocol is used to determine phosphoglucose isomerase (PGI) activity in cell or microbial extracts. It is applicable to enzyme activity assays using microbial pellets from fermentation broth, cell lysate supernatants, and other soluble protein samples.
After glucose enters cells, it can be converted into pyruvate and lactate through glycolysis, or it can enter the pentose phosphate pathway to generate NADPH and ribose phosphate. HK, PGI, PFK, and G6PDH correspond respectively to glucose phosphorylation after uptake, G6P/F6P interconversion, ...