Antimicrobial activity studies on a trypsin–chymotrypsin protease inhibitor obtained from potato

• Published in: Biochemical and biophysical research communications 2005-05, Vol.330 (3), p.921-927
• Main Authors: Kim, Jin-Young, Park, Seong-Cheol, Kim, Mi-Hyun, Lim, Hak-Tae, Park, Yoonkyung, Hahm, Kyung-Soo
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Anti-infective agents; Antimicrobial activity; Candida albicans; Chymotrypsin - antagonists & inhibitors; Chymotrypsin - metabolism; Hemolysis - drug effects; Humans; Kunitz family; Micrococcus - drug effects; Mitosporic Fungi - drug effects; Molecular Sequence Data; Molecular Weight; Plant Proteins - chemistry; Plant Proteins - isolation & purification; Plant Proteins - pharmacology; Rhizoctonia solani; Sequence Alignment; Serine Proteinase Inhibitors - chemistry; Serine Proteinase Inhibitors - isolation & purification; Serine Proteinase Inhibitors - pharmacology; Solanum tuberosum; Solanum tuberosum - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Trypsin - metabolism; trypsin–chymotrypsin protease inhibitor
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2005.03.057

A 5.6 kDa trypsin–chymotrypsin protease inhibitor was isolated from the tubers of the potato ( Solanum tuberosum L cv. Gogu) by extraction of the water-soluble fraction, dialysis, ultrafiltration, and C18 reversed-phase high performance liquid chromatography. This inhibitor, which we named potamin-1 (PT-1), was thermostable and possessed antimicrobial activity but lacked hemolytic activity. PT-1 strongly inhibited pathogenic microbial strains, including Candida albicans, Rhizoctonia solani, and Clavibacter michiganense subsp. michiganinse. Automated Edman degradation showed that the N-terminal sequence of PT-1 was NH 2-DICTCCAGTKGCNTTSANGAFICEGQSDPKKPKACPLNCDPHIAYA-. The sequence had 62% homology with a serine protease inhibitor belonging to the Kunitz family, and the peptide inhibited chymotrypsin, trypsin, and papain. This protease inhibitor, PT-1, was composed of polypeptide chains joined by disulfide bridge(s). Reduced PT-1 almost completely lost its activity against fungi and proteases indicating that disulfide bridge is essential for its protease inhibitory and antifungal activity. These results suggest that PT-1 is an excellent candidate as a lead compound for the development of novel oral or other anti-infective agents.