Biosynthetic features and properties of xylose isomerases from Arthrobacter nicotianae, Escherichia coli, and Erwinia carotovora subsp

Abstract

Abstract -The characteristics of xylose isomerase biosynthesis in the bacteria Arthrobacter nicotianae BIM B-5, Erwinia carotovora subsp atroseptica jn42xylA , and Escherichia coli HB101 xylA have been studied. The bacteria produced the enzyme constitutively. Out of the carbon sources studied, D -glucose and D -xylose were most favorable for the biosynthesis of xylose isomerase in E. carotovora subsp. atroseptica , but the least appropriate in terms of the enzyme production efficiency in E. coli . Minimum and maximum levels of xylose isomerase formation in A. nicotianae were noted, respectively, during D -xylose and sucrose utilization. An addition to the D -xylose-containing nutrient medium of 0.1-1.5% D -glucose did not affect the enzyme synthesis in A. nicotianae , but suppressed it in Erwinia carotovora subsp. atroseptica (by 7% at the highest concentration) and Escherichia coli (by 63 and 75% at concentrations of 0.1 and 1.0%, respectively). The enzyme proteins produced by the bacteria exhibited the same substrate specificity and electrophoretic mobility (PAGE) as xylose isomerase A. nicotianae , although insignificant differences in the major physicochemical properties were noted