Good lesson and well explained.

I've always found it difficult to explain to laymen about the role of enzymes (in general). I explain that they are proteins, and they facilitate ("catalyze") chemical reactions. In my experience it is difficult to convey the mechanism (if known), or even the general concept of enzyme catalysis via assisting chemical bond transitions--once an interested inquirer associates "enzyme" and "protein," those preconceived notions of "nutrition" and "dietary intake" distract from my attempts to explain reaction mechanisms and thus seem like irrelevant concepts. It's much easier to talk nerdy to fellow scientists, but laypeople in general have seen too many TV commercials butchering our terminology.