β-Glucoside Activators of Mung Bean UDP-Glucose: β-Glucan Synthase 1: II. Comparison of Effects of an Endogenous β-Linked Glucolipid with Synthetic

n -Alkyl (C 6 -C 12 ) β- d -monoglucopyranosides have been found to be highly potent activators of mung bean β-glucan synthase in vitro , increasing the V max of the enzyme as much as 60-fold and with K a values as low as 10 micromolar. Activation is highly specific for the β-linked terminal glucose residue; other alkyl glycosides such as, octyl-α-glucoside, dodecyl β-maltoside, 6-lauryl sucrose, 6-lauryl glucose, which lack this structure, are ineffective as activators. Based on the similarities in their structure and effects on β-glucan synthesis under a variety of conditions, it is proposed that the alkyl β-glucosides are structural analogs of the native glucolipid activator of β-glucan synthase isolated from mung bean extracts.