The enzymic degradation of starch by holotrich Protozoa from sheep rumen

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Abstract
The action of the debranching enzyme R-enzyme, [alpha]-amylase and [beta]-amylase on starch stored by holotrich ciliates from the sheep rumen has verified that this starch is amylopectin. A comparison of various enzyme activities present in aqueous extracts of purified preparations of the single organisms Isotricha and Dasytricha has been made. In the presence of 15% maltotriose, holotrich [alpha]-amylase is inhibited but phosphorylase activity is unaffected. Holotrich starch is synthesized by the phosphorolytic mechanism common to plants and animals. Two [alpha]-amylases specific to Isotricha and Dasytricha have been resolved by zone electrophoresis of holotrich extracts on starch columns. These amylases differ in optimum pH, electrophoretic mobility and isoelectric points. They are not activated by Ca++ or Cl- ions. Zone-electrophoretic separation of phosphorylase and amylase was unsuccessful owing to adsorption of phosphorylase on the column.