The effect of ascorbate on proteolytic enzyme activities in fish.

In vitro studies showed that an ascorbic acid concentration of 15 mM depressed the trypsin activity in three fish species by 50%, whereas dehydroascorbic acid and ascorbic sulfate did not inhibit trypsin or chymotrypsin activities. However, this inhibitory action is unlikely in vivo because ascorbic acid is rapidly oxidized in the digestive tract content to the dehydroascorbic acid.