Proteolytic activity of a yeast cell wall lytic Arthrobacter species

Aims: To investigate properties of the proteolytic activity of a yeast cell wall lytic soil bacterium identified as an Arthrobacter species. Methods and Results: The organism was grown at pH 7.5 and 30degreesC in shake flasks on media with different complex subtrates. Highest proteolytic activity assayed with azocaseine was detected in media with wheat gluten. In addition, l-leucine, l-alanine exopeptidase activity and esterase activity were found. The proteolytic activity showed stability up to pH 12, with a maximum at pH 11. The temperature optimum was at 55degreesC, but there was a loss in enzyme activity of 50% within 2 h. The proteolytic activity was inhibited by 3,4-dichloroisocumarin, whereas there was little or no effect with EDTA, pepstatin A or E64. Conclusions: The proteolytic activity is highly alkaline stable. The formation of the enzyme can be induced by media with high protein content.