Lactate dehydrogenase of trout: hybridization in vivo and in vitro

Speckled trout and lake trout contain five forms of lactate dehydrogenase, but a diflerent electrophoretic distribution of isozymes characterizes each species. The hybrid splake, which is produced artificially by fertilizing lake trout eggs with speckled trout sperm, contains nine isozymes. This comnplement of isozymeg In vivo could be produced in vitro by recombination of subunits from tissues of the parent species. In the splake trout, this complement is the result of heterozygosity at the gene locus responsible for synthesis of LDH-5. Extracts of trout eyes contain at least two additional forms of LDH which could not be demonstrated in other tissues.

Lactic and Malic Dehydrogenases in Human Spermatozoa

Human spermatozoa, representing a homogeneous population of postmitotic cells, contain five electrophoretically distinct lactic dehydrogenases and two malic dehydrogenases. This indicates that molecular heterogeneity of enzymes is characteristic of the individual cell and is not a reflection of heterogeneity of cell types within a tissue.