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Protein Trypsin Inhibitor from Potato Tubers

T. A. Revina, G. V. Kladnitskaya, N. G. Gerasimova, E. L. Gvozdeva, and T. A. Valueva*

Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia; fax: (495) 954-2732; E-mail: valueva@inbi.ras.ru

* To whom correspondence should be addressed.

Received April 24, 2009; Revision received May 18, 2009
A protein of 22 kDa designated as PKTI-22 was isolated from potato tubers (Solanum tuberosum L., cv. Istrinskii) and purified to homogeneity using CM-Sepharose CL-6B ion-exchange chromatography. The protein efficiently suppressed the activity of trypsin, affected chymotrypsin less, and did not affect subtilisin Carlsberg. The N-terminal sequence of PKTI-22 (20 amino acid residues) was found to be highly homologous with the amino acid sequences of the potato Kunitz-type proteinase inhibitors of group B (PKPI-B) that were aligned from the corresponding gene sequences and was identical to the sequence (from the 2nd to the 20th residue) of the recombinant protein PKPI-B10. These data together with the observed similarity of the properties of two proteins indicate that the PKTI-22 protein is encoded by the PKPI-B10 gene.
KEY WORDS: Kunitz-type proteinase inhibitors, trypsin, potato tubers

DOI: 10.1134/S0006297910010050