Two-dimensional electrophoresis in the analysis of a mixture of human sublingual and submandibular salivary proteins.

Complex protein mixtures of unstimulated human sublingual and submandibular saliva were fractionated by two-dimensional (2-D) gel electrophoresis, visualized by silver staining and then analysed by immunostaining. Specific proteins were identified by incubation with specific antibody and peroxidase-conjugated second antibody (Western blot). Electrophoresis and silver staining revealed over 50 protein components in 2 microliter of unconcentrated mixture. The Western-blot technique allowed detection of protein spots of plasma origin when an antibody against whole serum was used, but only the albumin spot could be found. Albumin, secretory IgA, acid phosphatase and alpha-amylase were identified with specific antibodies.