I have no idea what in the world is an enzyme drink.
As far as I am concerned... enzymes are proteins. You drink/eat it, it goes into your stomach... maybe aid digestion for a short while, then it will get digested like any other proteins.
So seriously, I think it's a fad... and it's just some marketing talk to fool consumers who don't know better.

Most probably it's the protein and amino acid composition of the enzymes that proves to be valuable. In this case, birds' nest can also be considered enzyme drink what... saliva of swallows is full of enzymes. Or another enzyme food you guys can consider... papaya. It's full of the enzyme papain --- which is a great in digesting proteins. Eat a slice after your steak... works better than Eno.

Hah hah Youngkies...
Based on 4Rings definition... it certainly is an enzyme drink. So is soy sauce and tapai. Heh heh!