Purification and Partial Characterization of Thermoactinomyces Vulgaris Amylases

An α-amylase from Thermoactinomyces vulgaris has been purified about 100-fold. Its optimum pH was between 5.9 and 7.0, and the maximum rate was achieved at 60 °C. In the absence of substrate, the enzymes were more stable at pH 5.9 than at higher or lower pH values; inactivation was rapid at pH 7.0. Temperatures of 70 °C or greater also caused rapid denaturation of the enzyme in the absence of substrate. Three major peaks of amylase activity were detected when purified enzyme preparations were passed through Sephadex G-75 columns. At least two of these amylases were interconvertible. Four or five T. vulgaris proteinases also were separated, using ion exchange column chromatography.