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Characterization of alanyl aminopeptidase from insecticide resistant and susceptible strains of Musca domestica L.
Author(s) -
AHMED Sohail,
WAKIL Waqas,
MANTLE David,
WILKINS Richard M.,
KWON Yong Jung
Publication year - 2008
Publication title -
entomological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 20
eISSN - 1748-5967
pISSN - 1738-2297
DOI - 10.1111/j.1748-5967.2008.00157.x
Subject(s) - biology , aminopeptidase , proteases , pepstatin , biochemistry , amino acid , pmsf , serine , enzyme , alanine , carboxypeptidase , hydrolysis , protease , leucine
To investigate the high activity of intracellular proteases in insecticide resistant strains of Musca domestica L., purification by anion‐exchange chromatography and gel filtration of one of the enzymes, alanyl aminopeptidase (Ala AP), in three strains of Musca domestica was carried out. The fractions collected by gel filtration of soluble homogenates of the three strains (571ab, 17bb and Cooper) showed a single peak of Ala AP activity. Partially purified Ala AP of the three strains showed high activity at pH 7.5. The presence or absence of Ca 2+ in the assay medium did not produce any difference in activity of Ala AP in the 571ab and Cooper strains, but there was a significant difference in the 17bb strain. The activity of Ala AP in all three strains was essentially unaltered in the presence of inhibitors of serine (PMSF), cysteine (E‐64) proteases and carboxypeptidases (pepstatin). Ala AP hydrolyzed alanine amino methylcoumarin (Ala‐AMC) maximally, followed by phenyl alanine amino methylcoumarin (Phe‐AMC), leucyl amino methylcoumarin (Leu‐AMC) and ornithine amino methylcoumarin (Orn‐AMC). Ala AP from the three strains showed differential activity towards various substrates. The comparison of alanyl aminopeptidase's activity from different sources is discussed.