Structural characteristics of the N-glycans of two isoforms of prostate-specific antigens purified from human seminal fluid

• Published in: Biochimica et biophysica acta Vol. 1525; no. 1; pp. 149 - 160
• Main Authors: Okada, Toyohiro, Sato, Yuji, Kobayashi, Norifumi, Sumida, Kyoichi, Satomura, Shinji, Matsuura, Shuji, Takasaki, Masaru, Endo, Tamao
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 16.02.2001
• Subjects: Carbohydrate Sequence; Carbohydrate structure; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Exoglycosidase sequencing; Humans; Male; Molecular Sequence Data; Oligosaccharides - chemistry; Oligosaccharides - isolation & purification; Polysaccharides - chemistry; Polysaccharides - isolation & purification; Prostate cancer; Prostate-specific antigen; Prostate-Specific Antigen - chemistry; Prostate-Specific Antigen - immunology; Prostate-Specific Antigen - isolation & purification; Protein Isoforms - chemistry; Protein Isoforms - isolation & purification; Semen - chemistry; Semen - immunology; Seminal fluid; Exoglycosidase sequencing; Seminal fluid; Prostate-specific antigen; PSA, prostate-specific antigen; RCA, Ricinus communis agglutinin; Carbohydrate structure; Prostate cancer; 2AB, 2-aminobenzamide; gu, glucose unit; HPLC, high performance liquid chromatography
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/S0304-4165(00)00182-3

Prostate-specific antigen (PSA) is a glycosylated chymotrypsin-like serine protease and is found mainly in prostatic tissue and seminal fluid. We purified two forms of PSA (PSA-A and PSA-B) from human seminal fluid with p I values of approx. 7.2 and approx. 6.9, respectively. To characterize the N-glycans of the two isoforms, the sugar chains were liberated by hydrazinolysis followed by N-acetylation, and derivatized with 2-aminobenzamide. Both PSA-A and PSA-B contained mono- and disialylated sugar chains, although PSA-B had a much higher content of the latter. After removal of sialic acid residues by sialidase digestion, mono- and biantennary N-glycans and three outer chain moieties (Galβ1-4GlcNAcβ1-, GlcNAcβ1-, GalNAcβ1-4GlcNAcβ1-) were found in both samples. However, the ratios of each N-glycan were different. These results indicate that PSA-A and PSA-B differ not only in their sialic acid contents, but also in their outer chain features.