The Macroglobulins

WHEN normal human serum is subjected to the gravitational force of ultracentrifugation the nonlipid-bearing proteins separate into three major components. The three components were at first identified as the A, G and M peaks. The A component, which contains the largest amount of protein, sediments most slowly; it consists mostly of albumin whence the designation "A". The G component is intermediate in size and rate of sedimentation; it is almost entirely gamma globulin and was thus designated "G". The smallest of the three peaks sediments with great rapidity because the protein molecules of which it is composed have a molecular . . .