Proteolytic enzymes of thermophilic bacteria-part I

Abstract

1. The thermophilic bacteria Bacillus thermophilus, B. aerothermophilus andB. thermoacidurans produce powerful proteinases which can be detected in the culture filtrates. 2. These proteinases resemble tryptases in their optimum hydrogenion requirements and hydrolyse gelatin and casein readily and albumins sparingly, unless the albumin has been previously denatured. 3. In addition to the proteinases these thermophilic bacteria also produce a polypeptidase capable of hydrolysing peptone, but this enzyme appears in culture filtrates much later than the proteinases. 4. Velocity of gelatin hydrolysis by these proteinases varies directly as the square root of time and percentage of hydrolysis varies directly with the enzyme concentration. 5. Relationship of substrate concentration and rate of hydrolysis shows that in case of gelatin Michaelis and Menton's equation is applicable and that an intermediate enzyme-substrate complex consisting of one molecule each of the enzyme and the substrate is probably formed before the substrate is hydrolysed.