Immunological relatedness of two isozymes of 3-phosphoglycerate kinase from the mouse.

Two isozymes of 3-phosphoglycerate kinase (ATP:3-phospho-D-~ycerate 1 -phosphotransferase, EC 2.7.2.3, PGK) are known to be present in mammalian tissues. PGK-I ** is found in all somatic tissues, and its structural locus is X-linked in humans [l] , kangaroos [2] and mice [3] .PGK-2 has been detected only in the sperm and testis of a number of mammals; however, there are exceptions where it has been found in somatic cells (kangaroo, dog, fox [4] ). Alleles determining electrophoretic variation map to chromosome 17 in the mouse [.5] . These two isozymes were purified in our laboratory, and their biochemical properties compared [6]. They were highly similar in their biochenlical properties even though the two loci must have been separated for over 100 million years [7]. To further explore the relatedness of these isozymes, antisera against the two PGK isozymes were produced separately, and their immunological properties were compared. The results of these studies suggest some antigenic relatedness between these two PGK isozymes.