Accumulation of environmental chitin in the lungs can lead to pulmonary fibrosis, characterized by inflammatory infiltration and fibrosis in acidic chitinase (Chia)-deficient mice. Transgenic expression of Chia in these mice ameliorated the symptoms, indicating the potential of enzyme supplementation as a promising therapeutic strategy for related lung diseases. This study focuses on utilizing hyperactivated human Chia, which exhibits low activity. We achieved significant activation of human Chia by incorporating nine amino acids derived from the crab-eating monkey (Macaca fascicularis) Chia, known for its robust chitin-degrading activity. The modified human Chia retained high activity across a broad pH spectrum and exhibited enhanced thermal stability. The amino acid substitutions associated with hyperactivation of human Chia activity occurred species specifically in monkey Chia. This discovery highlights the potential of hyperactivated Chia in treating pulmonary diseases resulting from chitin accumulation in human lungs.

• Klíčová slova
• acidic chitinase (Chia), amino acid substitutions, chitin, enzyme engineering, evolution, exon swapping, hyperactivation, primate lineage, treating pulmonary diseases,
• MeSH
• chitin metabolismus   MeSH
• chitinasy * genetika   metabolismus   chemie   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• myši MeSH
• stabilita enzymů MeSH
• substituce aminokyselin MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CHIA protein, human MeSH Prohlížeč
• chitin MeSH
• chitinasy * MeSH

Chitooligosaccharides exhibit several biomedical activities, such as inflammation and tumorigenesis reduction in mammals. The mechanism of the chitooligosaccharides' formation in vivo has been, however, poorly understood. Here we report that mouse acidic chitinase (Chia), which is widely expressed in mouse tissues, can produce chitooligosaccharides from deacetylated chitin (chitosan) at pH levels corresponding to stomach and lung tissues. Chia degraded chitin to produce N-acetyl-d-glucosamine (GlcNAc) dimers. The block-type chitosan (heterogenous deacetylation) is soluble at pH 2.0 (optimal condition for mouse Chia) and was degraded into chitooligosaccharides with various sizes ranging from di- to nonamers. The random-type chitosan (homogenous deacetylation) is soluble in water that enables us to examine its degradation at pH 2.0, 5.0, and 7.0. Incubation of these substrates with Chia resulted in the more efficient production of chitooligosaccharides with more variable sizes was from random-type chitosan than from the block-type form of the molecule. The data presented here indicate that Chia digests chitosan acquired by homogenous deacetylation of chitin in vitro and in vivo. The degradation products may then influence different physiological or pathological processes. Our results also suggest that bioactive chitooligosaccharides can be obtained conveniently using homogenously deacetylated chitosan and Chia for various biomedical applications.

• Klíčová slova
• FACE method, acidic chitinase, block-type chitosan, chitin, chitooligosaccharides, random-type chitosan,
• MeSH
• chitinasy chemie   metabolismus   MeSH
• chitosan chemie   metabolismus   MeSH
• difrakce rentgenového záření MeSH
• hydrolýza MeSH
• koncentrace vodíkových iontů * MeSH
• myši MeSH
• oligosacharidy chemie   metabolismus   MeSH
• orgánová specificita MeSH
• plíce metabolismus   MeSH
• substrátová specifita MeSH
• žaludek metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chitinasy MeSH
• chitosan MeSH
• oligochitosan MeSH Prohlížeč
• oligosacharidy MeSH

Diet of the crab-eating monkey (Macaca fascicularis) consists of both plants and animals, including chitin-containing organisms such as crabs and insects. This omnivorous monkey has a high expression of acidic chitinase (CHIA) in the stomach and here, we report on its enzymatic properties under different conditions. When we compared with Mus musculus CHIA (Mm-CHIA), Macaca fascicularis CHIA (Mf-CHIA) exhibits higher chitinolytic activity at broad pH (1.0-7.0) and temperature (30-70 ℃) range. Interestingly, at its optimum pH (5.0), Mf-CHIA showed the highest activity at 65 °C while maintaining it at robust levels between 50 and 70 °C. The degradation efficiency of Mf-CHIA was superior to Mm-CHIA toward both polymeric chitin as well as an artificial chromogenic substrate. Our results show that unique features of Mf-CHIA including its thermostability warrant the nomination of this enzyme for potential agricultural and biomedical applications.

• MeSH
• chitin chemie   MeSH
• chitinasy chemie   MeSH
• Escherichia coli MeSH
• koncentrace vodíkových iontů MeSH
• Macaca fascicularis MeSH
• myši MeSH
• oligosacharidy chemie   MeSH
• polymery chemie   MeSH
• polysacharidy chemie   MeSH
• rekombinantní proteiny chemie   MeSH
• sacharidy chemie   MeSH
• teplota MeSH
• žaludek metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chitin MeSH
• chitinasy MeSH
• oligosacharidy MeSH
• polymery MeSH
• polysacharidy MeSH
• rekombinantní proteiny MeSH
• sacharidy MeSH