Frog lysozyme. II. Isozymes of lysozyme during the larval development of the leopard frog, Rana pipiens

Eight isozymes of lysozyme were found differentially distributed among six developmental stages of Rana pipiens. Qualitative changes during early development involved a progressive loss of the more basic isozymes which then reappeared between metamorphosis and maturity. Though the egg contained five isozymes, only two were present by early metamorphosis including one not found in the egg. By metamorphic climax, the four isozymes in the egg were regained and one additional form appeared. By maturity, two less basic forms appeared giving a total of eight isozymes. From hatching to early metamorphosis, lysozyme units per animal increased, but lysozyme units/mg dry weight remained unchanged. Both lysozyme units per animal and units/mg dry weight increased sharply towards the end of metamorphosis.