TY - JOUR
T1 - Characterization of a β-glucosidase produced by a high-specific growth-rate mutant of Cellulomonas flavigena
AU - Barrera-Islas, Gaspar A.
AU - Ramos-Valdivia, Ana C.
AU - Salgado, Luis M.
AU - Ponce-Noyola, Teresa
PY - 2007/4
Y1 - 2007/4
N2 - The mutant strain PN-120 of Cellulomonas flavigena produces a β-glucosidase that is 10-fold more active than the corresponding enzyme isolated from the parental strain. These enzymes were partially purified through Q Sepharose and Bio-Gel filtration. A single protein band was detected on polyacrylamide-gel electrophoresis/zymogram using 4-methylumbelliferyl-β-D- glucoside. On sodium dodecyl sulfate-PAGE, the enzyme displayed three protein bands, suggesting that in C. flavigena the enzyme is oligomeric with a molecular mass of 210 kDa. On purification, the specific activity of β-glucosidase isolated from PN-120 was increased 16-fold and showed three times more affinity for cellobiose than the enzyme of the parental strain; nevertheless, the optimum pH and temperature were similar for both enzymes. The kinetic parameters suggested that the increase in the activity of the enzyme, from the mutant strain, was caused by a mutation that affects the catalytic site of the enzyme. The partial amino-acid sequence of the isolated enzyme confirmed that it is a β-glucosidase because of its homology with other β-glucosidases produced by cellulolytic bacteria and fungi.
AB - The mutant strain PN-120 of Cellulomonas flavigena produces a β-glucosidase that is 10-fold more active than the corresponding enzyme isolated from the parental strain. These enzymes were partially purified through Q Sepharose and Bio-Gel filtration. A single protein band was detected on polyacrylamide-gel electrophoresis/zymogram using 4-methylumbelliferyl-β-D- glucoside. On sodium dodecyl sulfate-PAGE, the enzyme displayed three protein bands, suggesting that in C. flavigena the enzyme is oligomeric with a molecular mass of 210 kDa. On purification, the specific activity of β-glucosidase isolated from PN-120 was increased 16-fold and showed three times more affinity for cellobiose than the enzyme of the parental strain; nevertheless, the optimum pH and temperature were similar for both enzymes. The kinetic parameters suggested that the increase in the activity of the enzyme, from the mutant strain, was caused by a mutation that affects the catalytic site of the enzyme. The partial amino-acid sequence of the isolated enzyme confirmed that it is a β-glucosidase because of its homology with other β-glucosidases produced by cellulolytic bacteria and fungi.
UR - http://www.scopus.com/inward/record.url?scp=33947419339&partnerID=8YFLogxK
U2 - 10.1007/s00284-006-0105-7
DO - 10.1007/s00284-006-0105-7
M3 - Artículo
C2 - 17334847
SN - 0343-8651
VL - 54
SP - 266
EP - 270
JO - Current Microbiology
JF - Current Microbiology
IS - 4
ER -