Triose Phosphate Isomerase (TPI or TIM: EC 5.3.1.1) is an important enzyme for glycolysis. It reversibly interconverts dihydroxyacetone phosphate and glyceraldehyde-3-phosphate, thus maintaining the equilibrium of these two triose phosphates. TPI connects glycolysis to pentose phosphate pathway and lipid metabolism. It is a stable homodimer found in almost all organisms. In humans, TPI deficiency is a rare multisystem disorder and leads to progressive neurological dysfunction, characterized by hemolytic anemia, cardiomyopathy and progressive neuromuscular impairment. Assay Genie's Triose Phosphate Isomerase Activity Assay kit provides a quick and easy way for monitoring Triose Phosphate Isomerase activity in a variety of samples. In this kit, Triose Phosphate Isomerase converts dihydroxyacetone phosphate into glyceradehyde-3-phosphate, which reacts with the Enzyme Mix & Developer to form a colored product with strong absorbance at 450 nm. The assay is simple, sensitive, & high-throughput and can detect Triose Phosphate Isomerase activity as low as 40 mU/ml.

Figure: (a) NADH Standard Curve. (b) Kinetic measurement of Triose Phosphate Isomerase (TPI) activity in various samples. (c) Relative TPI activity was calculated in lysates prepared from rat muscle (0.5 µg), MCF-7 cells (0.8 µg), and HeLa cells (0.84 µg). Assays were performed following the kit protocol.