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A new type of beta-N-Acetylglucosaminidase from hydrogen-producing Clostridium paraputrificum M-21

Authors :
Huazhong, Li
Kenji, Morimoto
Tetsuya, Kimura
Kazuo, Sakka
Kunio, Ohmiya
Source :
Journal of bioscience and bioengineering. 96(3)
Publication Year :
2003

Abstract

A beta-N-acetylglucosaminidase gene (nag84A) was cloned from Clostridium paraputrificum M-21 in Escherichia coli. The nag84A gene consists of an open reading frame of 4647 by encoding 1549 amino acids, with a deduced molecular weight of 174,311, which have a catalytic domain belonging to family 84 of the glycoside hydrolases. Nag84A was purified from a recombinant E. coli and characterized. Although Nag84A exhibited high homology to the hyaluronidase from Clostridium perfringens, it did not degrade hyluronic acid. The enzyme hydrolyzed chitooligomers such as di-, tri-, tetra-, penta- and hexa-N-acetylchitohexaose, and synthetic substrates such as 4-methylumbelliferyl N-acetyl beta-D-glucosaminide [4-MU-(G1cNAc)], but did not hydrolyze 4-MU-beta-D-glucoside, 4-MU-alpha-D-glycoside, 4-MU-alpha-D-GlcNAc, 4-MU-alpha-D-galactoside, 4-MU-beta-D-xyloside, PNP-beta-D-galactoside, and PNP-alpha-D-xyloside. The enzyme was optimally active at 50 degrees C and pH 6.5, and the apparent K(m) and V(max) values for 4-MU-(GlcNAc) were 8.5 microM and 1.39 micromol/min/mg of protein, respectively. SDS-PAGE, zymogram, and immunological analyses suggested that Nag84A was inducible by ball-milled chitin. Since Nag84A has a high molecular weight with a family 84 catalytic domain with high homology to hyaluronidases but no hyaluronidase activity, the enzyme is a novel beta-N-acetylglucosaminidase different from others reported having low molecular weights and belonging to family 3 and family 18.

Details

ISSN :
13891723
Volume :
96
Issue :
3
Database :
OpenAIRE
Journal :
Journal of bioscience and bioengineering
Accession number :
edsair.pmid..........f7bfe5f6e1fba217639dd3fd111853c9