Biochemical characterization of an extracellular β-glucosidase from the fungus, Penicillium italicum, Isolated from rotten citrus peel
- Authors
- Park, A.-R.; Hong, J.H.; Kim, J.-J.; Yoon, J.-J.
- Issue Date
- 2012
- Keywords
- β-Glucosidase; Cellulolytic fungi; Characterization; Identification; Purification
- Citation
- Mycobiology, v.40, no.3, pp.173 - 180
- Indexed
- SCOPUS
KCI
- Journal Title
- Mycobiology
- Volume
- 40
- Number
- 3
- Start Page
- 173
- End Page
- 180
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/110647
- DOI
- 10.5941/MYCO.2012.40.3.173
- ISSN
- 1229-8093
- Abstract
- A β-glucosidase from Penicillium italicum was purified with a specific activity of 61.8 U/mg, using a chromatography system. The native form of the enzyme was an 88.5-kDa tetramer with a molecular mass of 354 kDa. Optimum activity was observed at pH 4.5 and 60°C, and the half-lives were 1,737, 330, 34, and 1 hr at 50, 55, 60, and 65°C, respectively. Its activity was inhibited by 47% by 5 mM Ni2+. The enzyme exhibited hydrolytic activity for p-nitrophenyl-β-D-glucopyranoside (pNP-Glu), p-nitrophenyl-β-D-cellobioside, p-nitrophenyl-β-D-xyloside, and cellobiose, however, no activity was observed for p-nitrophenyl-β-D-lactopyranoside, p-nitrophenyl-β-D-galactopyranoside, carboxymetyl cellulose, xylan, and cellulose, indicating that the enzyme was a β-glucosidase. The kcat/Km (s-1 mM-1) values for pNP-Glu and cellobiose were 15,770.4 mM and 6,361.4 mM, respectively. These values were the highest reported for β-glucosidases. Non-competitive inhibition of the enzyme by both glucose (Ki = 8.9 mM) and glucono-δ-lactone (Ki = 11.3 mM) was observed when pNP-Glu was used as the substrate. This is the first report of non-competitive inhibition of β-glucosidase by glucose and glucono-δ-lactone. © The Korean Society of Mycology.
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Collections - College of Life Sciences and Biotechnology > Division of Environmental Science and Ecological Engineering > 1. Journal Articles
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