Trace Proteins in Biological Fluids. IV. Physicochemical Properties and Sites of Formation of γ-Trace and β-Trace Proteins. ∗

Summary

Two isolated trace proteins of beta and gamma mobility from human cerebrospinal fluid were studied to determine their sedimentation coefficients in the ultra-centrifuge and their sites of formation. Two sedimentation peaks were obtained for β-trace, 0.5 S and 2.1 S, and one for γ-trace, 1.6 S. The two values for β-trace were thought to be due to polymerization. Production of y-trace in vitro occurred in a number of Rhesus monkey tissues, but was most striking in the submaxillary gland where the protein was present in extractable amounts. A few cultures of choroid plexus, fimbriae of the Fallopian tube, and testis showed C¹⁴-amino acid incorporation into β-trace.