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Identification of isopeptidase activity in the midgut of insects: Purification, properties and nutritional ecology of a Hofmannophila pseudospretella (Lepidoptera: Oecophoridae) larval enzyme
Author(s) -
Simpson Robert M.,
Christeller John T.
Publication year - 2010
Publication title -
insect science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 45
eISSN - 1744-7917
pISSN - 1672-9609
DOI - 10.1111/j.1744-7917.2010.01325.x
Subject(s) - midgut , biology , lepidoptera genitalia , larva , enzyme , insect , molecular mass , digestive enzyme , enzyme assay , zoology , biochemistry , botany , lipase
A γ‐glutamyl transpeptidase (isopeptidase) has been purified 580‐fold to homogeneity from the midgut of keratinophagous larvae of Hofmannophila pseudospretella . The enzyme is a single polypeptide of molecular mass 80 kDa. The enzyme was identified by its hydrolytic activity against the synthetic substrate, γ‐glutamyl‐AMC, its molecular mass and inhibition profile compared to other γ‐glutamyl transpeptidases. The enzyme is low or absent from most other insect digestive systems apart from other keratinophagous lepidopteran larvae and predatory carabids. While isopeptide bonds are present in high levels of the proteins in the diet of keratinophages, their presence in the diet of predatory beetles has not been established.