Amino acid sequence of the predominant basic protein in human seminal plasma.

The predominant basic protein in liquefied human seminal plasma is the major degradation product of the gel-forming protein secreted by the seminal vesicles. The amino acid sequence of this basic protein is presented. The basic protein contains 52 amino acid residues. It is devoid of cysteine, methionine, tryptophan, and leucine, but contains seven histidine residues located in the NH2-terminal half of the molecule. The calculated Mr of 5753 is in close agreement with that obtained from gel filtration in guanidine-HCl on Sephacryl S-200 (Mr = 6000).