Serine proteinase like activity in apolipophorin iii from the hemolymph of desert locust, schistocerca gregaria

Zulfiqar A. Malik, Sumaira Amir, István Venekei

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Apolipophorin III (apoLp-III) has been known as a lipid transport protein of insects. Recent studies indicated the involvement of apoLp-III in immune reactions and in the control of cell destruction, but no enzymatic activity has so far been detected. In the present study, a protease from the hemolymph of Schistocerca gregaria was purified to homogeneity and its enzymatic activity was examined. Identity as chymotrypsin-like proteinase was established by its high affinity toward bulky aromatic substrates and its catalytic specificity for amide or ester bonds on the synthetic substrates, Suc-Ala-Ala-Pro-Xaa-AMC (where Xaa was Phe, Tyr, Trp, and Lys, and AMC is 7-amino-4-methyl-coumarin) and thiolbenzyl ester substrate Suc-Ala-Ala-Pro-Phe-SBzl. The sensitivity for serine protease and chymotrypsin-specific covalent inhibitors, PMSF, TPCK, and noncovalent inhibitors SGCI, showed that it is a chymotrypsin-like proteinase. It showed its maximum activity at pH 8.0 and 55°C for the hydrolysis of Suc-Ala-Ala-Pro-Tyr-AMC. According to similarities in the amino terminal sequence, molar mass (19 kDa) and retention on reversed-phase analytical high-performance liquid chromatography (HPLC) column, this protein is S. gregaria homologue of Locusta migratoria apoLp-III. Our data suggest that apoLp-III also has an inherent proteolytic activity. Results indicated that S. gregaria apoLp-III is a good catalyst and could be used as a biotechnological tool in food processing and in agricultural biotechnology.

Original languageEnglish (US)
Pages (from-to)26-41
Number of pages16
JournalArchives of Insect Biochemistry and Physiology
Volume80
Issue number1
DOIs
StatePublished - Jun 1 2012

Keywords

  • Apolipophorin III
  • Locusta migratoria
  • Proteolytic activity
  • Schistocerca gregaria

ASJC Scopus subject areas

  • Physiology
  • Biochemistry
  • Insect Science

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