Comparative biochemical studies of milks—I. Electrophoretic analysis of milk proteins

1. 1. Paper electrophoretic patterns of caseins and whey proteins from milks of forty species of mammals representing eight orders are presented. Each species has a distinct pattern and related species have similar patterns. 2. 2. Three types of casein patterns were found. The most primitive has a single fast-moving component which is strongly adsorbed by paper. The second type has a prominent slow-moving component and a faster component which is adsorbed. The third type has two sharply differentiated components. 3. 3. In eight species in which whey and blood serum were compared the whey contained components with the mobility of blood serum albumin and gamma globulins. 4. 4. Milks from the primitive orders contained fewer unique whey protein components than milks of more advanced orders. 5. 5. An electrophoretic component tentatively identified as lysozyme appears in whey protein patterns of certain carnivores and perissodactyls.