LIPOPHILIN, A NOVEL HETERODIMERIC PROTEIN OF HUMAN TEARS

We identified a novel heterodimeric protein, lipophilin AC, in human t ears. One of its components, lipophilin A (69 residues; mass, 7575.1; pI, 9.47) was homologous to the C1 and C2 components of prostatein ('e stramustine-binding protein'), the major secreted protein of rat prost ate. Human lipophilin C (77 residues; mass, 8854.1; pI, 4.94) was homo logous to the rat prostatein C3 component and to human mammaglobin, a protein overexpressed in some mammary carcinomas. Tear lipophilins A a nd C expand the roster of human uteroglobin superfamily members and pr ovide models for exploring these typically steroid-regulated and stero id-binding molecules. (C) 1998 Federation of European Biochemical Soci eties.