Premium
A β‐ N ‐acetylhexosaminidase from Penicillium oxalicum implicated in its cell‐wall degradation
Author(s) -
Rodriguez J.,
CopaPatino J.L.,
Reyes F.,
PérezLeblic M.I.
Publication year - 1994
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.1994.tb00947.x
Subject(s) - humanities , library science , chemistry , art , computer science
High β‐ N ‐acetylhexosaminidase (EC.3.2.1.52) activity was detected during autolysis of Penicillium oxalicum . Purification of the enzyme to homogeneity yielded an enzyme with a molecular weight of 132 000 Da by gel filtration and 71 900 Da by SDS polyacrylamide gel electrophoresis, suggesting a dimeric structure. The enzyme is an acidic protein with a pl of 5.0. Optimal activity was at pH 4.0 and 40°C, with a K m of 0.80 mmol 1 ‐1 for p ‐nitrophenyl‐β‐ N ‐acetylglucosaminide and 1.03 mmol 1 ‐1 for p ‐nitrophenyl‐β‐ N ‐acetylgalactosaminide. The K i with the competitive inhibitor O‐(2‐acetamido‐2‐deoxy‐D‐glucopyranosylidene) amino‐ N ‐phenylcarbamate was 1 μmol 1 ‐1 . Hg 2+ , Ag + and Fe 3+ were effective inhibitors. β‐ N ‐acetylhexosaminidase hydrolysed chitobiose, chitotriose, chitotetrose and chitopentose to monomer to an extent of 92, 74, 44 and 17% respectively in 40 min. This enzyme, in conjunction with a purified endochitinase from P. oxalicum , hydrolysed a cell‐wall chitin fraction isolated from this fungus, with the production of N ‐acetylglucosamine.