4(b) is evidence of a single isoform, unless two or more isoforms of α-glucosidase have the same molecular mass. The enzyme trehalase, which has a narrow range of optimum pH (5.5–6.5) predominates in the posterior midgut (Fig. 10(a) and appears to be attached to the microvilli (Fig. 10(b). The specific activity of trehalase measured in purified microvilli using trehalose as substrate increased by approximately 8 times relative to that of the crude material. Epacadostat solubility dmso We could not measure any activity from the midgut homogenate when using isomaltose, a disaccharide composed of two glucose residues connected

by an α-1,6 glycosidic linkage, as Selleck PI3K inhibitor a substrate. Despite the lack of activity with isomaltose, the digestion of glycogen and amylopectin implies the disruption of the branches formed by α-1,6 linkages. Dextran, a polysaccharide produced by some microorganisms and that consists of glucose residues connected by α-1,6 glycosidic linkages, with some branches beginning from α-1,3

linkages, was not digested by the larvae in our assay conditions. Cellulose, a polysaccharide commonly present in the detritus ingested by the larvae, apparently cannot be digested by the larvae. According to our results, carboxymethyl cellulose, a soluble variant of cellulose, was not perceptively digested by the gut homogenate of the L. longipalpis larvae (data not shown). Accordingly, the homogenate was practically unable to hydrolyze the synthetic substrate p-Np-β-d-glucopyranoside

in our assay conditions ( Table 1). The activities of several other glycoside hydrolases were screened in the larval midgut using p-Np-derived substrates. The activities of the soluble and membrane-bound enzymes are presented in Table 1 at both pH 6 and 8.5. According to the results presented in Table 1, only the substrates p-Np-α-d-glucopyranoside and p-Np-N-acetyl-β-d-glucosaminide were markedly hydrolyzed MYO10 by midgut-associated enzymes under the assay conditions. These activities could be attributed to the enzymes α-d-glucosidase and N-acetyl-β-d-hexosaminidase. This N-acetyl-β-d-hexosaminidase might be part of a chitinolytic system. Similar to the α-glucosidase and trehalase, the N-acetyl-β-d-hexosaminidase was also present in purified microvilli. The specific activity of this enzyme measured in purified microvilli using p-Np-N-acetyl-β-d-glucosaminide as a substrate increased approximately 6 times relative to that of the crude material. Traces of activity using p-Np-N-acetyl-β-d-galactosaminide, p-Np-β-d-galactopyranoside and p-Np-α-d-mannopyranoside were also observed.