Isolation and amino-acid sequence of two inhibitors of serine proteinases, members of the squash inhibitor family, from Echinocystis lobata seeds

D Stachowiak; A Polanowski; G Bieniarz; T Wilusz

Isolation and amino-acid sequence of two inhibitors of serine proteinases, members of the squash inhibitor family, from Echinocystis lobata seeds

Acta Biochim Pol. 1996;43(3):507-13.

Authors

D Stachowiak¹, A Polanowski, G Bieniarz, T Wilusz

Affiliation

¹ Institute of Biochemistry, University of Wrocław, Poland.

PMID: 8922034

Abstract

Two serine proteinase inhibitors (ELTI I and ELTI II) have been isolated from mature seeds of Echinocystis lobata by ammonium sulfate fractionation, methanol precipitation, ion exchange chromatography, affinity chromatography on immobilized anhydrotrypsin and HPLC. ELTI I and ELTI II consist of 33 and 29 amino-acid residues, respectively. The primary structures of these inhibitors are as follows: ELTI I KEEQRVCPRILMRCKRDSDCLAQCTCQQSGFCG ELTI II RVCPRILMRCKRDSDCLAQCTCQQSGFCG The inhibitors show sequence similarity with the squash inhibitor family. ELTI I differs from ELTI II only by the presence of the NH2-terminal tetrapeptide Lys-Glu-Glu-Gln. The association constants (Ka) of ELTI I and ELTI II with bovine-trypsin were determined to be 6.6 x 10(10) M-1, and 3.1 x 10(11) M-1, whereas the association constants of these inhibitors with cathepsin G were 1.2 x 10(7) M-1, and 1.1 x 10(7) M-1, respectively.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Chromatography, Affinity
Chromatography, High Pressure Liquid
Chromatography, Ion Exchange
Molecular Sequence Data
Serine Proteinase Inhibitors / chemistry
Serine Proteinase Inhibitors / isolation & purification*
Vegetables / chemistry*

Substances

Serine Proteinase Inhibitors