With barbital buffer pH 8.6, which protein fraction migrates fastest toward the anode?

With barbital buffer pH 8.6, which protein fraction migrates fastest toward the anode?

• A. Albumin
• B. Alpha1-globulin
• C. Beta-globulin
• D. Gamma-globulin

Answer: (A)

Proteins in a buffer at a high pH carry a net negative charge, and in electrophoresis toward the anode (the positive electrode) the speed mainly follows charge density and size. Albumin has a strong negative charge at pH 8.6 (its isoelectric point is well below this pH) and is relatively small compared with many globulins, giving it the highest charge-to-size ratio among the major fractions. This combination makes albumin migrate toward the anode faster than the larger, often less negatively charged globulin fractions. The gamma globulins, in particular, are large and move more slowly, while the alpha and beta globulins are intermediate in size and charge. So albumin appears as the fastest-moving fraction toward the anode.

Proteins in a buffer at a high pH carry a net negative charge, and in electrophoresis toward the anode (the positive electrode) the speed mainly follows charge density and size. Albumin has a strong negative charge at pH 8.6 (its isoelectric point is well below this pH) and is relatively small compared with many globulins, giving it the highest charge-to-size ratio among the major fractions. This combination makes albumin migrate toward the anode faster than the larger, often less negatively charged globulin fractions. The gamma globulins, in particular, are large and move more slowly, while the alpha and beta globulins are intermediate in size and charge. So albumin appears as the fastest-moving fraction toward the anode.