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https://hdl.handle.net/2440/23950
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dc.contributor.author | Hrmova, M. | - |
dc.contributor.author | Burton, R. | - |
dc.contributor.author | Biely, P. | - |
dc.contributor.author | Lahnstein, J. | - |
dc.contributor.author | Fincher, G. | - |
dc.date.issued | 2006 | - |
dc.identifier.citation | Biochemical Journal, 2006; 399 Part 1(1):77-90 | - |
dc.identifier.issn | 0264-6021 | - |
dc.identifier.issn | 1470-8728 | - |
dc.identifier.uri | http://hdl.handle.net/2440/23950 | - |
dc.description.abstract | A family GH5 (family 5 glycoside hydrolase) (1,4)-beta-D-mannan endohydrolase or beta-D-mannanase (EC 3.2.1.78), designated HvMAN1, has been purified 300-fold from extracts of 10-day-old barley (Hordeum vulgare L.) seedlings using ammonium sulfate fractional precipitation, followed by ion exchange, hydrophobic interaction and size-exclusion chromatography. The purified HvMAN1 is a relatively unstable enzyme with an apparent molecular mass of 43 kDa, a pI of 7.8 and a pH optimum of 4.75. The HvMAN1 releases Man (mannose or D-mannopyranose)-containing oligosaccharides of degree of polymerization 2-6 from mannans, galactomannans and glucomannans. With locust-bean galactomannan and mannopentaitol as substrates, the enzyme has K(m) constants of 0.16 mg x ml(-1) and 5.3 mM and kcat constants of 12.9 and 3.9 s(-1) respectively. Product analyses indicate that transglycosylation reactions occur during hydrolysis of (1,4)-beta-D-manno-oligosaccharides. The complete sequence of 374 amino acid residues of the mature enzyme has been deduced from the nucleotide sequence of a near full-length cDNA, and has allowed a three-dimensional model of the HvMAN1 to be constructed. The barley HvMAN1 gene is a member of a small (1,4)-beta-D-mannan endohydrolase family of at least six genes, and is transcribed at low levels in a number of organs, including the developing endosperm, but also in the basal region of young roots and in leaf tips. A second barley enzyme that participates in mannan depolymerization through its ability to hydrolyse (1,4)-beta-D-manno-oligosaccharides to Man is a family GH1 beta-D-mannosidase, now designated HvbetaMANNOS1, but previously identified as a beta-D-glucosidase [Hrmova, MacGregor, Biely, Stewart and Fincher (1998) J. Biol. Chem. 273, 11134-11143], which hydrolyses 4NP (4-nitrophenyl) beta-D-mannoside three times faster than 4NP beta-D-glucoside, and has an action pattern typical of a (1,4)-beta-D-mannan exohydrolase. | - |
dc.description.statementofresponsibility | Maria Hrmova, Rachel A. Burton, Peter Biely, Jelle Lahnstein and Geoffrey B. Fincher | - |
dc.language.iso | en | - |
dc.publisher | Portland Press | - |
dc.source.uri | http://dx.doi.org/10.1042/bj20060170 | - |
dc.subject | Catalytic amine acid | - |
dc.subject | (1 | - |
dc.subject | 4)-beta-D-mannan endohydrolase | - |
dc.subject | beta-D-mannosidase | - |
dc.subject | family GH1 and GH5 glycoside hydrolases | - |
dc.subject | Hordeum vulgare | - |
dc.subject | transglycosylation | - |
dc.title | Hydrolysis of (1,4)-beta-D-mannans in barley (Hordeum vulgare L.) is mediated by the concerted action of (1,4)-beta-D-mannan endohydrolase and beta-D-mannosidase | - |
dc.type | Journal article | - |
dc.identifier.doi | 10.1042/BJ20060170 | - |
pubs.publication-status | Published | - |
dc.identifier.orcid | Hrmova, M. [0000-0002-3545-0605] | - |
dc.identifier.orcid | Burton, R. [0000-0002-0638-4709] | - |
dc.identifier.orcid | Lahnstein, J. [0000-0002-4202-1403] | - |
Appears in Collections: | Agriculture, Food and Wine publications Aurora harvest 6 |
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