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Multiple alpha-gala...
Multiple alpha-galactosidases from Aspergillus niger: purification, characterization, and substrate specificities
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Ademark, Pia (författare)
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Larsson, M (författare)
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- Tjerneld, Folke (författare)
- Lund University,Lunds universitet,Biokemi och Strukturbiologi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biochemistry and Structural Biology,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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- Stålbrand, Henrik (författare)
- Lund University,Lunds universitet,Biokemi och Strukturbiologi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biochemistry and Structural Biology,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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(creator_code:org_t)
- 2001
- 2001
- Engelska.
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Ingår i: Enzyme and Microbial Technology. - 0141-0229. ; 29:6-7, s. 441-448
- Relaterad länk:
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http://dx.doi.org/10...
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https://lup.lub.lu.s...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Enzymes with α-galactosidase activity are produced by many organisms, often in multiple forms. Here we compare the biochemical and hydrolytic properties of four major α-galactosidase forms (α-gal I-IV) that were purified from the culture filtrate of Aspergillus niger. α-Gal II, III and IV appear to be isoforms of the same enzyme, and N-terminal amino acid sequence data suggest that they are closely related or identical to A. niger AglB in family 27 of the glycosyl hydrolases. α-Gal I is a completely different enzyme that belongs to family 36. α-Gal I had an isoelectric point of 4.15 and appears to be a tetramer composed of four 94-kDa subunits. α-Gal II, III and IV were dimers with monomeric molecular masses of 64 kDa and isoelectric points of 4.5, 4.7 and 4.8, respectively. α-Gal II-IV were stable when incubated for 17 h at 50°C and pH 2–5, whereas α-gal I was most stable at pH 5–6. All enzymes had maximal catalytic activity at pH 4.5 and 60°C, and hydrolyzed melibiose, raffinose and stachyose. α-Gal II-IV also degraded galactomanno-oligosaccharides and released 66% of the galactose side groups from polymeric locust bean gum galactomannan. α-Gal I released galactose from locust bean gum only in combination with A. niger β-mannosidase. Kinetic experiments showed that α-gal I hydrolyzed p-nitrophenyl-α-Image-galactopyranoside and melibiose more efficiently than α-gal II-IV. The distinct hydrolytic and biochemical properties of α-gal I and α-gal II-IV further signifies the difference between α-galactosidases of family 27 and 36.
Ämnesord
- NATURVETENSKAP -- Biologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences (hsv//eng)
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