The mechanism of polysaccharide production from sucrose. 2

Abstract

Levan synthesis by the levansucrase of Aerobacter levanicum proceeds at an opt. rate in mixtures containing 5% sucrose buffered at pH 5-5.8. A Levansucrase Unit (L.U.) is defined as the minimum amt. of enzyme which induces production of 100 mg. of levan/100 ml. in reaction mixtures of 3 ml. containing 5% of sucrose at pH 5 after incubation for 2 hrs. at 37[degree]. The time-action curve of soluble levansucrose in the presence a of non-limiting conc. of sucrose and a sufficiency of enzyme follows initially a linear course, but later bends sharply and flattens as unidentified inhibitors come into play. The final absolute levan yield is a function of the initial sucrose and enzyme supply when low concns. of substrate or enzyme are employed, but is independent of either when they are increased sufficiently.