Submitted to: Biochemical Archives
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2007
Publication Date: 5/2/2008
Publication URL: www.sciencedirect.com doi: 10.1016/j.biochi.2007.11.002
Citation: Goptar, I.A., Filippova, I.Y., Lysogorskaya, E.N., Oksenoit, E.S., Vinokurov, K.S., Zhuzhikov, D.P., Bulushova, N.V., Zalunin, I.A., Dunaevsky, Y.E., Belozersky, M.A., Oppert, B.S., Elpidina, E.N. 2008. Localization of two post-proline cleaving peptidases in the midgut of Tenebrio molitor larvae. Biochemie 90: 508-514. Interpretive Summary: Storage pests digest foods that contain high levels of the imino acid proline, which require a special enzyme for complete digestion. We isolated several such enzymes from the gut of the yellow mealworm, and we demonstrated that one of the enzymes is involved in digestion. This information can be used to identify new inhibitors to disrupt pest digestion of food.
Technical Abstract: Two soluble post-proline cleaving peptidase activities, PPCP1 and PPCP2, were demonstrated in the midgut of Tenebrio molitor larvae with the substrate benzyloxycarbonyl-L-alanyl-L-proline p-nitroanilide. Both activities were serine peptidases. PPCP1 was active in acidic buffers, with maximum activity at pH 5.3, and was located mainly in the more acidic anterior midgut lumen. The dynamics of PPCP1 activity and the total activity of soluble digestive peptidases in the course of food digestion were similar, supporting the hypothesis that the enzyme participates in protein digestion. These data are the first report of the role of a post-proline cleaving peptidase in digestion. PPCP2 is a nondigestive soluble tissue enzyme evenly distributed along the midgut. An increase in the activity of PPCP2 was observed in buffers of pH 5.6-8.6 and was maximal at pH 7.4. The sensitivity of PPCP2 to inhibitors and the effect of pH are similar to those of prolyl oligopeptidases with a cysteine residue near the active site.