A comparative study of the proteins in the body fluids of animals

Abstract

A new gel medium for the electrophoretic separation of proteins was developed and the separation properties were compared with that of polyacrylamide gel. The new medium. is based on the combination of Sephadex G-2 5 Superfine and acrylamide (1,4:1) into one separating gel. It separates certain body fluid proteins into more components than can be attained with conventional polyacrylamide gel electrophoresis. This new technique was used to study the proteins of various animals and the possible influence of physical exercise, heat exposure and fever on the electrophoretic properties and concentrations of proteins in the body fluids of these animals. Emphasis was laid on albumin since this protein separated into tv main fractions, an upper and a lower albumin band. These electrophoretically distinct albumins were of approximate]y equal concentrations and also cross reacted immunologically. It was further shown that circulating albumin concentration may be underestimated by dye binding assays, due to the fact that the lower albumin fraction does not bind to many dyes. Limited biochemical analysis suggested that the lower albumin fraction may be bound to different molecules than the upper albumin. This differentiation in carrying capacity results in microheterogeneity of the albumin causing differences in electrophoretic mobilities. Possible functional differences of the two albumins were also studied during physical exercise, heat exposure and fever conditions. It was found that human subjects not participating in regular physical exercise had relatively increased lower albumin concentrations as compared to the same subjects after