Esterase isozymes of the hen's oviduct.

Esterase isozymes of magnum, isthmus and uterus of three strains of Single Comb White Leghorn hens were examined by zone electrophoresis on starch gels. Although three regions (I, II and III) of esterase activity were observed, the electrophoretic system was optimized to characterize the pattern of up to five zones of esterase activity that were identified in Region I. These esterases were classified as aliesterases based on reactions in the presence of various substrates and inhibitors. No genetic polymorphisms were observed for these isozymes. However, two of these isozymes were perceived to have an electrophoretic mobility slightly faster in patterns of the magnum of layers than in the isthmus, uterus, and magnum of non-layers. It was shown that egg albumen was present in relatively high quantities in the magnum of layers and that egg albumen, when added to supernatant preparations of isthmus, uterus and magnum of non-layers, caused the faster electrophoretic mobility of these two esterase isozymes. No relation between specific gravity of eggs laid by hens and presence of various Region I esterase isozymes could be detected.