A polyacrylamide-gel electrophoretic study of human tear proteins.

The protein composition of normal and pathological tears was studied by polyacrylamide-gel (disc) electrophoresis. Polyacrylamide-gel electrophoresis was shown to detect at least 14 fractions in 2-10 microliters of native tears. A comparison was made between the protein composition of normal tears and serum. The most characteristic bands in the tear-protein pattern were identified by parallel electrophoresis of tears, serum, human milk and purified egg-white lysozyme. The identified fractions were specific tear prealbumin, serum albumin, transferrin, lactoferrin and lysozyme. An unidentified major tear-protein component was also described. The tear-protein pattern was divided into six zones: (1) prealbumin zone; (2) post-albumin zone; (3) post-transferrin zone; (4) macroglobulin zone; (5) basic globulin zone; (6) prelactoferrin zone. A significant rise in the level of serum albumin and transferrin was demonstrated in tears from cases of acute catarrhal conjunctivitis. The optimal circumstances were discussed under which major and minor tear components and basic and acidic tear proteins can be determined simultaneously. Polyacrylamide-gel electrophoresis is recommended as a useful method to study the various diseases of the anterior segment of the eye.