From Aspergillus niger
Activity: >60,000 unit/g solid
Unit Definition: One unit will liberate 1.0 μmole of glucose from cellulose in one hour at pH 5.0 and 37°C.
Similar to Cellulase 101308, but slightly more soluble in water and with a different unit of activity.
Description: Cellulase refers to a group of enzymes which, acting together, hydrolyze cellulose. It has been reviewed by Emert, et al.5 and Whitaker.10
The enzymatic mechanism whereby certain microorganisms can quite rapidly and completely degrade cellulose is not yet understood. Reese, et al.8 proposed that at least two steps are involved: first, a prehydrolytic step wherein anhydroglucose chains are swollen or hydrated and secondly, hydrolytic cleavage of the now susceptible polymers either randomly or endwise. The first step would involve an enzyme designated C1 and the second, hydrolytic enzymes termed Cc. A third type of enzyme is b-glucosidase.
Multi-enzyme cellulase complexes capable of converting cellulose to glucose contain at least three distinct enzyme components which degrade native cellulose. The action of the C1 component on cellulose is not well defined. There is no evidence that the component hydrolyzes glucosidic bonds, but rather it appears that the C1 component disrupts the structure of native cellulose by weakening the hydrogen bonds. The action is required before hydrolysis of highly structured forms of cellulose (cotton, cyrstalline cellulose, wood, etc.) can occur.
The Cc component consist of b-1,4-glucanases, Exo-b-1,4-glucanase successively removes single glucose units from the nonreducing end of the cellulose chain, while endo-b-1,4-glucanases randomly hydrolyze the interior glucosidic bonds of cellulose liberating oligomers of lower molecular weight.
The b-glucosidases, including cellobiose, are primarily active on the smaller molecular weight cellulose hydrolysates. During cellulose breakdown they are active on the dimers and oligomers of cellulose.
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