An electrophoretically detectable modification of glucosephosphate isomerase in mouse spermatozoa

Cellulose acetate electrophoresis of glucosephosphate isomerase (GPI) from mouse testis and spermatozoa revealed a minor band which is not seen in electropherograms of GPI from other tissues. The minor band is associated equally with the two electrophoretic variants of GPI examined. Treatment of tissue extracts with various enzymes, enzyme inhibitors or thiol reagents failed to alter the appearance or position of the minor bands in sperm and testis GPI, or to induce their appearance in GPI from other tissues. No minor bands were seen in electropherograms of testis GPI from immature males, or from males whose testes lack spermatozoa for genetic reasons.