Testis specific phosphoglycerate kinase B in mouse.

Mammals possess two genetically distinct forms of phosphoglycerate kinase (PGK). Only the X-linked PGK-A isozyme is detectable by electrophoresis of somatic and ovarian tissues of the mouse and of most other eutherian mammals studied to date. The PGK-B isozyme is highly active in testes and epididymides which contain spermatozoa, as well as in semen. PGK-B activity is first detectable in testes of 22-day-old mice and shows rapid increase concomitant with germ cell proliferation until day 40,after which activity increases only slightly. Two allelic isozymes (F and S) in mice express equal enzyme activity and are inherited in an autosomal codominant manner. One is equally as heat stable as PGK-A; the other is heat labile. Two of the 33 strains tested express neither F nor S, but do express a faintly staining PGK band which is of slightly faster mobility than F and which is absent from the other stains. This may represent a third allelic isozyme of PGK-B with reduced enzyme activity.