1986
DOI: 10.1002/arch.940030607
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Partial characterization of a major gut thiol proteinase from larvae of Callosobruchus maculatus F.

Abstract: Much of the proteolytic activity in the digestive tract of Callosobruchus maculatus larvae can be attributed to a thiol proteinase(s) that hydrolyzes 3H]methemoglobin by larval gut homogenates. Proteolytic activity in the larval gut was located in the lumen contents and thus appears to play a major role in extracellular digestion. The pH of the larval midgut is slightly acidic, and midgut contents exhibit a negative redox potential, conditions supporting the activity of a thiol proteinase. The significance of… Show more

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Cited by 90 publications
(51 citation statements)
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“…Proteolysis of the rGSII-Y134D or BSA was reduced substantially by trans-epoxysuccinyl-L-leucylamido (4-guanidino)-butane (E-64), an irreversible inhibitor of cysteine proteases (data not shown). This result is in accordance with earlier evidence indicating that cysteine proteases are the major protein digestive enzymes used by cowpea bruchid (34,38). The rGSII protein did not prevent proteolysis of BSA by C. maculatus gut extract (data not shown), indicating that biochemical stability and insecticidal activity of rGSII is not due to inherent protease inhibitor activity.…”
Section: Resultssupporting
confidence: 93%
See 1 more Smart Citation
“…Proteolysis of the rGSII-Y134D or BSA was reduced substantially by trans-epoxysuccinyl-L-leucylamido (4-guanidino)-butane (E-64), an irreversible inhibitor of cysteine proteases (data not shown). This result is in accordance with earlier evidence indicating that cysteine proteases are the major protein digestive enzymes used by cowpea bruchid (34,38). The rGSII protein did not prevent proteolysis of BSA by C. maculatus gut extract (data not shown), indicating that biochemical stability and insecticidal activity of rGSII is not due to inherent protease inhibitor activity.…”
Section: Resultssupporting
confidence: 93%
“…The physiological pH of C. maculatus larval midguts has been determined to be about 6.1 by using a pH microelectrode (34). However, the midgut contains a thiol-dependent protease with pH optimum at 5.0 (34).…”
Section: Resultsmentioning
confidence: 99%
“…Interestingly, arcelin has been shown to possess activity against the bruchid Zabrotes subfasciatus but not against another bean bruchid Acanthoscelides obtectus (19). Further, the pH optimum of inhibition of porcine a-amylase by P. vulgaris aAI is 5.7 (15), which is close to the pH of the cowpea weevil midgut contents (13). These data suggest that the bean aAI has evolved as one of the major determinants in protecting common bean from attack by bruchid beetles such as the cowpea weevil (10,16).…”
Section: And Discussionmentioning
confidence: 97%
“…This cleavage removes a small C-terminal peptide and makes the inhibitor ineffective against pancreatic a-amylase. Cys proteases rather than Ser proteases are abundant in larval midguts of bruchids and may be primarily responsible for protein digestion (Kitch and Murdock, 1986;Campos et al, 1989). However, prevention of proteolysis by protease inhibitors shows that the midgut protease responsible for the cleavage of aAI-1 is a Ser protease.…”
Section: How Do Bruchids Tolerate High Levels Of Aai In Beans?mentioning
confidence: 99%