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Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut.
Arch Insect Biochem Physiol. 2001 Dec; 48(4):206-16.AI

Abstract

Compartmentalization of proteinases, amylases, and pH in the midgut of Nauphoeta cinerea Oliv. (Blattoptera:Blaberidae) was studied in order to understand the organization of protein and starch digestion. Total proteolytic activity measured with azocasein was maximal at pH 11.5 both in anterior (AM) and posterior (PM) halves of the midgut, but the bulk of activity (67%) was found in PM. Total AM and PM preparations were fractionated on a Sephadex G-50 column and further analysed by means of activity electrophoresis and specific inhibitors and activators. The major activity in PM was classified as an unusual SH-dependent proteinase with M(r) 24,000 and pH optimum with synthetic substrate BApNA at 10.0. The enzyme was 43-fold activated in the presence of 1 mM DTT, insensitive to synthetic inhibitors of serine (PMSF, TLCK, TPCK) and cysteine (IAA, E-64) proteinases, strongly inhibited by STI, and displayed four active bands on zymograms. In PM, activities of trypsin-like, chymotrypsin-like, subtilisin-like, and cysteine proteinases were observed. Aspartic and metalloproteinases were not detected. In AM, activity of unusual SH-dependent proteinase also dominated and activity of chymotrypsin-like proteinase was observed, but their levels were much lower than in PM. Distribution of amylase activity, exhibiting an optimum at pH 6.0, was quite the opposite. The major part of it (67%) was located in AM. Treatment of amylase preparation with proteinases from AM and PM reduced amylase activity twofold. pH of the midgut contents was 6.0-7.2 in AM, 6.4-7.6 in the first and 8.8-9.3 in the second halves of PM. Thus, pH in AM is in good agreement with the optimal pH of amylase, located in this compartment, but the activity of proteinases, including the ability to degrade amylase, in such an environment is low. Active proteolysis takes place in the second half of PM, where pH of the gut is close to the optimal pH of proteinases.

Authors+Show Affiliations

A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia. elp@genebee.msu.suNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

11746565

Citation

Elpidina, E N., et al. "Compartmentalization of Proteinases and Amylases in Nauphoeta Cinerea Midgut." Archives of Insect Biochemistry and Physiology, vol. 48, no. 4, 2001, pp. 206-16.
Elpidina EN, Vinokurov KS, Gromenko VA, et al. Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut. Arch Insect Biochem Physiol. 2001;48(4):206-16.
Elpidina, E. N., Vinokurov, K. S., Gromenko, V. A., Rudenskaya, Y. A., Dunaevsky, Y. E., & Zhuzhikov, D. P. (2001). Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut. Archives of Insect Biochemistry and Physiology, 48(4), 206-16.
Elpidina EN, et al. Compartmentalization of Proteinases and Amylases in Nauphoeta Cinerea Midgut. Arch Insect Biochem Physiol. 2001;48(4):206-16. PubMed PMID: 11746565.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut. AU - Elpidina,E N, AU - Vinokurov,K S, AU - Gromenko,V A, AU - Rudenskaya,Y A, AU - Dunaevsky,Y E, AU - Zhuzhikov,D P, PY - 2001/12/18/pubmed PY - 2002/1/16/medline PY - 2001/12/18/entrez SP - 206 EP - 16 JF - Archives of insect biochemistry and physiology JO - Arch Insect Biochem Physiol VL - 48 IS - 4 N2 - Compartmentalization of proteinases, amylases, and pH in the midgut of Nauphoeta cinerea Oliv. (Blattoptera:Blaberidae) was studied in order to understand the organization of protein and starch digestion. Total proteolytic activity measured with azocasein was maximal at pH 11.5 both in anterior (AM) and posterior (PM) halves of the midgut, but the bulk of activity (67%) was found in PM. Total AM and PM preparations were fractionated on a Sephadex G-50 column and further analysed by means of activity electrophoresis and specific inhibitors and activators. The major activity in PM was classified as an unusual SH-dependent proteinase with M(r) 24,000 and pH optimum with synthetic substrate BApNA at 10.0. The enzyme was 43-fold activated in the presence of 1 mM DTT, insensitive to synthetic inhibitors of serine (PMSF, TLCK, TPCK) and cysteine (IAA, E-64) proteinases, strongly inhibited by STI, and displayed four active bands on zymograms. In PM, activities of trypsin-like, chymotrypsin-like, subtilisin-like, and cysteine proteinases were observed. Aspartic and metalloproteinases were not detected. In AM, activity of unusual SH-dependent proteinase also dominated and activity of chymotrypsin-like proteinase was observed, but their levels were much lower than in PM. Distribution of amylase activity, exhibiting an optimum at pH 6.0, was quite the opposite. The major part of it (67%) was located in AM. Treatment of amylase preparation with proteinases from AM and PM reduced amylase activity twofold. pH of the midgut contents was 6.0-7.2 in AM, 6.4-7.6 in the first and 8.8-9.3 in the second halves of PM. Thus, pH in AM is in good agreement with the optimal pH of amylase, located in this compartment, but the activity of proteinases, including the ability to degrade amylase, in such an environment is low. Active proteolysis takes place in the second half of PM, where pH of the gut is close to the optimal pH of proteinases. SN - 0739-4462 UR - https://www.unboundmedicine.com/medline/citation/11746565/Compartmentalization_of_proteinases_and_amylases_in_Nauphoeta_cinerea_midgut_ L2 - https://doi.org/10.1002/arch.10000 DB - PRIME DP - Unbound Medicine ER -