In this post, I link to and excerpt from emedicine.medscsape.com‘s [Interpritation Of] Serum Electrophoresis, Updated: Dec 16, 2021
Author: Sherilyn Alvaran Tuazon, MD.
All that follows is from the above resource.
Serum protein electrophoresis (SPEP) is an easy, inexpensive method of separating proteins based on their net charge, size, and shape. The 2 major types of protein present in the serum are albumin and the globulin proteins. Albumin is the major protein component of serum and represents the largest peak that lies closest to the positive electrode.  Globulins make up a much smaller fraction of the total serum protein but represent the primary focus of interpretation of serum protein electrophoresis. Five globulin categories are represented: alpha-1, alpha-2, beta-1, beta-2, and gamma, with the gamma fraction being closest to the negative electrode.