Structural studies on rat prostatic binding protein. The primary structure of component C2 from subunit S

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Prostatic binding protein is a major secretory glycoprotein in the rat ventral prostate.
• Component C2 is the polypeptide specific for subunit S of this protein.

Purpose of the Study:

• To determine the complete amino acid sequence of component C2.
• To elucidate the structural features of component C2.
• To investigate the evolutionary relationship between component C2 and component C1.

Main Methods:

• Manual Edman degradation of enzymatic and chemical fragments.
• S-carboxamidomethylation of component C2 and native subunit S.
• Chemical cleavage using cyanogen bromide.

Main Results:

• The amino acid sequence of component C2 (92 amino acids, MW 10619) was established.
• Component C2 is a slightly acidic polypeptide with blocked N-terminus and three cysteines.
• A polar region (residues 23-34) and two hydrophobic segments (C-terminal) were identified.
• High sequence homology between component C2 and component C1 was observed.

Conclusions:

• The detailed structure of component C2 was elucidated.
• The findings suggest an evolutionary relationship between prostatic binding protein subunits.
• This study provides foundational data for understanding prostatic glycoprotein structure and function.