A study of additional forms of the human sperm lactate dehydrogenase isoenzyme

Unusual isoenzymes of the sperm-specific lactate dehydrogenase detected in the seminal plasma of some infertile men were investigated using selective precipitation by antisera followed by electrophoretic resolution. The presence of two C subunit types was established: type I is a polymer of the four common C-subunits and type II consists of four C-subunits. Subunits of types I and II combine to form 5 sperm-specific binomially distributed lactate dehydrogenase isoenzymes. These results suggest the existence of two alleles at the c locus.