Chracterization of tumor M2-pk (pyruvati kinase) enzyme in breast carcinoma

Pyruvate kinase (EC 2.7.1.40, a key enzyme inATP: Pyruvate-O-phosphotransferase),glycolysis, catalyzes conversion of phosphoenolpyruvate (PEP) into pyruvate withregeneration of adenosine triphosphate (ATP). Pyruvate kinase is a tetramer. In mammaliantissues, four distinct isoenzymes of pyruvate kinase are found: M1-type; M2-type ; L-type,and R-type. These isoenzymes differ in kinetic and regulatory properties and localization indifferent tissues.The key regulator of the metabolic alterations found in tumor cells is the glycolyticisoenzyme pyruvate kinase type M2 that is generally expressed in all proliferating cells andoverexpressed in all tumor cells investigated to date. During carcinogenesis a shift in thepyruvate kinase isoenzyme equipment always takes place, such that the tissue-specificisoenzymes disappear (such as M1-PK in muscle and brain, L-PK in liver and kidney, and R-PK in red blood cells), and M2-PK is expressed. M2-PK can exist in a highly activetetrameric form with a high affinity to its substrate, phosphoenolpyruvate (PEP), and in adimeric form with a low PEP affinity. The dimeric form of M2-PK is virtually inactive atcellular PEP concentration.An enzyme-linked immunosorbent assay (ELISA) for the determination of Tumor M2-PK in ethylenediaminetetraacetic acid (EDTA)-plasma is available from ScheBo Biotech AG.In accordance with results from immunohistological staining, the amount of Tumor M2-PK inETDA-plasma samples from patients with renal cell carcinoma, pancreatic, lung, breast, andcolon cancer directly reflected the metastatic state of the tumors.Carcinoma of the breast, the third most common cancer worldwide, accounts for thehighest morbidity and mortality. In the present study, pyruvate kinase specific activity ofplasma and tissue samples were studied with Beutler and ELISA method in 92 patients.Pyruvate kinase activities of plasma samples are belonging to control and patient gruopswhich were studied both ELISA and Beutler methods were compared and were foundsignificant result(p<0.001). Also, pyruvate kinase aktivities of tumor and normal tissuesamples which studied with Beutler method were compared and the results were foundp< 0.001.Key Words: Breast Carcinoma, Pyruvate Kinase, Tumor M2- pyruvate kinase.