I've been hearing quantum superposition and tunneling as a factor in enzyme mechanisms at least since I was a grad student (circa 1988ish). It was all the rage that perhaps it was the main enzymatic mechanism; but, it grew a little less popular as more 'conventional' explanations seemed to provide acceptable kinetic models. "sources"? too many to list, but just search for quantum effects and enzymes and set your last date to something like 1990ish, like here:
https://scholar.google.com/scholar?q=enzyme+mechanism+quantu...
Yes, I think the work that was published in this area was mostly speculative. I want links to mainstream stuff that I can put a little more trust in, like the work done at LBL on photosynthesis and entanglement.
Just look at some of those names in the authorship of that haphazard search link i included. Richards, Pullman, McElroy, Bhattacharyya, Pauling ... If you can't put trust in some of those folks then you won't find it in general. (whatever the hell "trust" has to do with good science, notwithstanding)
Pauling was a genius, great contributions to chemistry, but he also thought vitamin C was the cure for everything. I'm a "real scientist" and I can judge evidence for myself.\
Random searches on terms bring up a lot of stuff, but it takes time to evaluate everything. On the other hand, I'm already up to speed on the state of the art in protein chemistry, and I'm not seeing strong physical evidence from experimentalists supporting this.
