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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Stored Product Insect and Engineering Research » Research » Publications at this Location » Publication #339753

Research Project: Sustainable Management Strategies for Stored-Product Insects

Location: Stored Product Insect and Engineering Research

Title: Prolidase is a critical enzyme for complete gliadin digestion in Tenebrio molitor larvae

item TERESHCHENKOVA, VALERIIA - Moscow State University
item GOPTAR, IRINA - Moscow State University
item ZHUZHIKOV, DMITRY - Moscow State University
item BELOZERSKY, MIKHAIL - Moscow State University
item DUNAEVSKY, YAKOV - Moscow State University
item Oppert, Brenda
item FILIPPOVA, IRINA YU - Moscow State University
item ELPIDINA, ELENA - Moscow State University

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2017
Publication Date: 8/15/2017
Citation: Tereshchenkova, V.F., Goptar, I., Zhuzhikov, D.P., Belozersky, M.A., Dunaevsky, Y.E., Oppert, B.S., Filippova, I., Elpidina, E.N. 2017. Prolidase is a critical enzyme for complete gliadin digestion in Tenebrio molitor larvae. Archives of Insect Biochemistry and Physiology. 95(4):e21395.

Interpretive Summary: We have studied the enzymes in the gut of yellow mealworm larvae that contribute to the digestion of intractable proteins in their diet, mainly gliadins. This report constitutes the final in a series, a report on an enzyme identified as prolidase I. We have purified and characterized the chemical properties of the enzyme, and we have identified the messenger RNA (mRNA) encoding the enzyme. Both the mRNA and purified enzyme are found in the back of the gut, and we propose that this enzyme is involved in the final stages of digestion. These studies help to us to understand the digestive process in tenebrionids, as well as identify new strategies for control.

Technical Abstract: Prolidase is a proline specific metallopeptidase that cleaves imidodipeptides with C-terminal Pro residue. Prolidase was purified and characterized from the Tenebrio molitor larval midgut. The enzyme was localized in the soluble fraction of posterior midgut tissues, corresponding to a predicted cytoplasmic localization of prolidase according to the structure of the mRNA transcript. Expression of genes encoding prolidase and the major digestive PSP – dipeptidyl peptidase 4, were similar. The pH-optimum of T. molitor prolidase was 7.5, and the enzyme was inhibited by Z-Pro, indicating that it belongs to type I prolidases. In mammals, prolidase is particularly important in the catabolism of a proline-rich protein – collagen. We propose that T. molitor larval prolidase is a critical enzyme for the final stages of digestion of dietary proline-rich gliadins, providing hydrolysis of imidodipeptides in the cytoplasm of midgut epithelial cells. We propose that the products of hydrolysis are absorbed from the luminal contents by peptide transporters, which we have annotated in the T. molitor larval gut transcriptome. The origin of prolidase substrates in the insect midgut is discussed in the context of overall success of grain feeding insects.