Phosphoglycerate mutase isozyme marker for tissue differentiation in man.

In the course of population screening for genetically determined variation of the glycolytic enzymes in human brain [1], we have found electrophoretic evidence for tissue-specific isozymes of phosphoglycerate mutase (PGAM; E.C.2.7.5.3). PGAM reversibly converts 3-phosphoglycerate to 2-phosphoglycerate. Skeletal muscle PGAM migrates slowly, while PGAM from brain and other tissues migrates rapidly toward the anode in Tris-citrate (pH 7.5) or in Tris-EDTA-borate (pH 8.6) horizontal starch gels [2]. Extracts of heart muscle give a three-banded pattern of PGAM activity consistent with a dimer structure with a molecular weight of approximately 60,000 reported for chicken, rabbit, and sheep skeletal muscle and porcine kidney [3-6]. In this paper we report striking developmental and neoplastic transitions in the phenotype of PGAM in human tissues.