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Proteinase inhibitors in Nauphoeta cinerea midgut
Author(s) -
Elpidina Ele.,
Vinokurov Konstantin S.,
Rudenskaya Yuliya A.,
Dunaevsky Yakov E.,
Zhuzhikov Dmitry P.
Publication year - 2001
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.10001
Subject(s) - midgut , biology , biochemistry , botany , larva
Proteinase inhibitors were studied in the midgut of Nauphoeta cinerea Oliv. (Blattoptera: Blaberidae) in experimental conditions, excluding their nutritional origin. One trypsin inhibitor (TI) with M r 8,000 and two subtilisin inhibitors (SI1 and SI2) with M r 13,000 and 8,000 were detected after fractionation of total protein preparation on Sephadex G‐50. Ninety‐four percent of both types of inhibitors was located in anterior midgut (AM). TI was 120‐fold purified by FPLC‐chromatography on Mono Q. Its isoelectric point was 4.3. TI lost a large part of activity in acidic and especially in alkaline medium. TI, SI1, and SI2 effectively inhibited activities of endogenous proteinases from posterior midgut (PM) of the cockroach. A search for inhibitor of endogenous unusual SH‐dependent proteinase from AM revealed in AM a new inhibitor with M r 18,000. It was also inactivated in alkaline medium and was effective against proteinases from PM along with unusual SH‐dependent proteinase from AM. A mechanism of regulation of activity of midgut proteinases is proposed based on pH‐stability of inhibitors. Arch. Insect Biochem. Physiol. 48:217–222, 2001. © 2001 Wiley‐Liss, Inc.