|
KMID : 0364819760140030117
|
|
Korean Journal of Microbiology
1976 Volume.14 No. 3 p.117 ~ p.127
|
|
|
Studied on the Cellulolytic Enzymes of Stachybotrys atra; Partial purification of cellulase and effects of temperature, pH and metal ions on the enzyme
|
|
|
|
|
Abstract
|
|
|
|
A cellulase fraction (F IV-1) purified to about 8-folds was obtained from crude cellulase prepared from the wheat bran culture of S.atra. The partial purification of the enzyme was made by DEAE Sephadex and Sephdex cloumn chromatography in conjuction with ammonium sulfate precipitation. After standing at various pH´s for 22 hours at 20℃, F IV-1 was most stable at pH 5.0 but when the enzyme fraction was stood for 74 hours, the point of pH stability was raised to around pH 6.0-7.0. After heating at various temperatures for 1 hour, F IV-1 was most stable at 20℃. The optimal enzyme activities of F IV-1 were seen at pH 6.0 and 50℃. The optimal concentrations of Zn^++ and Ca^++ for the activities of crude cellulase were 6 and 4 mM respectively, but Ca^++ inhibited the enzyme activity at concentrations below 2 mM and above 6mM. Both Cu^++ and Mn^++ ions inhibited cellulase activities and a complete inactivation of crude cellulase was achieved at concentrations of 5 and 2 mM of ions respectively. When Na-CMC was used as substrate, the Km values of crude cellulase and F IV-1 were calculated to be 5 × 10^-4 and 2 × 10^-5 mM, and V values 32 and 1.35 mmoles/hour, respectively. The Ki values of Mn^++ for crude cellulase and F IV-1 were found to be 8 × 10^-2 and 3 × 10^-2 mM while those of Cu^++ were at 2 × 10^-1 and 1 × 10^-1 mM respectively. Both Mn^++ and Cu^++ showed competitive inhibition with substrate.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
|
|