Acidic mammalian chitinase is a proteases-resistant glycosidase in mouse digestive system

Misa Ohno, Masahiro Kimura, Haruko Miyazaki, Kazuaki Okawa, Riho Onuki, Chiyuki Nemoto, Eri Tabata, Satoshi Wakita, Akinori Kashimura, Masayoshi Sakaguchi, Yasusato Sugahara, Nobuyuki Nukina, Peter O. Bauer, Fumitaka Oyama

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Chitinases are enzymes that hydrolyze chitin, a polymer of β-1, 4-linked N-acetyl-D-glucosamine (GlcNAc). Chitin has long been considered as a source of dietary fiber that is not digested in the mammalian digestive system. Here, we provide evidence that acidic mammalian chitinase (AMCase) can function as a major digestive enzyme that constitutively degrades chitin substrates and produces (GlcNAc)2 fragments in the mouse gastrointestinal environment. AMCase was resistant to endogenous pepsin C digestion and remained active in the mouse stomach extract at pH 2.0. The AMCase mRNA levels were much higher than those of four major gastric proteins and two housekeeping genes and comparable to the level of pepsinogen C in the mouse stomach tissues. Furthermore, AMCase was expressed in the gastric pepsinogen-synthesizing chief cells. The enzyme was also stable and active in the presence of trypsin and chymotrypsin at pH 7.6, where pepsin C was completely degraded. Mouse AMCase degraded polymeric colloidal and crystalline chitin substrates in the gastrointestinal environments in presence of the proteolytic enzymes. Thus, AMCase can function as a protease-resistant major glycosidase under the conditions of stomach and intestine and degrade chitin substrates to produce (GlcNAc)2, a source of carbon, nitrogen and energy.

Original languageEnglish
Article number37756
JournalScientific reports
Volume6
DOIs
Publication statusPublished - Nov 24 2016
Externally publishedYes

ASJC Scopus subject areas

  • General

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