title: Immunological control of scab mites: digestive enzymes as candidate compounds.
abstract: Phosphatases, C4 and C8 esterases, leucine and valine aminopeptidases, n-acetyl-beta-glucosaminidase, beta-glucosidase, beta-galactosidase and beta-glucuronidase were active in extracts of scab mites (Psoroptes spp.) raised on sheep or rabbits. Trypsin and chymotrypsin activities were not detected. Haemoglobin was hydrolysed by a detergent-soluble fraction of the mite extracts in a pH-dependent fashion with an optimum of pH 3-5. Acid proteinase activity was greater in mites raised on rabbits than in those raised on sheep. Inhibitors of cysteine, serine and metallo-proteinases failed to inhibit the hydrolysis of H-Pro-Thr-Glu-Phe-Phe(NO2)Arg-Leu-OH while pepstatin A, a specific inhibitor of aspartic proteinases, totally inhibited its hydrolysis at a concentration of 1 nM.
authors.affiliation: Department of Zoology, University of Aberdeen, Scotland, UK. a.j.nisbet@abdn.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: Nisbet
authors.forename: P F
authors.initials: PF
authors.lastname: Billingsley
mesh_terms: D000626:Aminopeptidases / Q000737:chemistry; D000818:Animals; D003124:Colorimetry / Q000662:veterinary; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry; D004950:Esterases / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry; D007930:Leucine / Q000031:analogs & derivatives / Q000737:chemistry; D008924:Mite Infestations / Q000517:prevention & control / Q000662:veterinary*; D008925:Mites / Q000201:enzymology* / Q000276:immunology; D010436:Pepstatins / Q000737:chemistry; D010664:Phenylmethylsulfonyl Fluoride / Q000737:chemistry; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry; D011480:Protease Inhibitors / Q000737:chemistry; D011817:Rabbits; D012756:Sheep; D013983:Tick Control / Q000379:methods*
chemical_list: D015853:Cysteine Proteinase Inhibitors; D006454:Hemoglobins; D010436:Pepstatins; D011480:Protease Inhibitors; C014195:Streptomyces pepsin inhibitor; D010664:Phenylmethylsulfonyl Fluoride; D004492:Edetic Acid; D004950:Esterases; D010744:Phosphoric Monoester Hydrolases; D006026:Glycoside Hydrolases; D000626:Aminopeptidases; D007930:Leucine; C024974:E 64; C031375:pepstatin