Abnormal circulating protein concentration Abnormal circulating globulin concentration Any deviation from the normal concentration of globulins in the blood circulation. Albumin makes up more than half of the total protein present in serum. The remaining blood proteins except albumin and fibrinogen (which is not in serum) are referred to as globulins. The globulin fraction includes hundreds of serum proteins including carrier proteins, enzymes, complement, and immunoglobulins. Most of these are synthesized in the liver, although the immunoglobulins are synthesized by plasma cells. Globulins are divided into four groups by electrophoresis. The four fractions are alpha1, alpha2, beta and gamma, depending on their migratory pattern between the anode and the cathode.