The hydrolytic activity of L-ascorbic acid

The ability of L-ascorbic acid to catalyze the liberation of 4-methylumbelliferone from 4-methylumbelliferyl-beta-D-N-acetylglucosaminide, 4-methylumbelliferyl-beta-D-glucuronide, 4-methylumbelliferyl-alpha-D-mannoside, and 4-methylumbelliferyl-beta-D-galactoside is documented. There is an apparent metal and oxygen dependency. The cleavage of two lipids was shown in addition to the hydrolysis of these fluorogenic glycosides. Galactose was liberated from galactosyl-6-[3H]ceramide and oleic acid from cholesterol-[1-14C]oleate by L-ascorbic acid under conditins usually used for in vitro incubations. In common with most in vitro systems, only a small percentage of substrate was degraded.