Parathymosin alpha: a peptide from rat tissues with structural homology to prothymosin alpha.

Abstract
A peptide, parathymosin .alpha., containing .simeq. 105 amino acid residues, was isolated from rat thymus, and the sequence of the first 30 residues at the NH2 terminus was determined. In this region, it shows 43% structural identity with thymosin .alpha.1 and prothymosin .alpha.. The common sequences do not include residues 2-9, which accounts for the poor reactivity of parathymosin .alpha. with an antibody directed against this epitope in thymosin .alpha.1. Parathymosin .alpha. appears to modulate the action of prothymosin .alpha. in protecting sensitive strains of mice against opportunistic infection with Candida albicans.