I know that's not that relevant to anyone actually studying or working with enzymes, which is probably why this is so hard to find out as a layman.
I'm working on very simplified school materials, designed to help young adults preparing for a rudimentary school degree. (German system)
They need a very basic introduction to chemistry in order to even be able to work with the recommended materials. When I explain what a Molecule is, I try to make them understand that they can be as simple as Water or incredibly complex. For the latter I chose alpha-Amylase as an example, because the students already know the enzyme from biology and it would certainly help to illustrate the scale of atoms, if they understood, that such 'huge' molecules exist in their saliva. Now of course I could just write "...thousands of atoms...", but in my experience that wouldn't have the same impact as providing more concrete figures. From what I gathered so far, not every alpha-Amylase is built exactly the same way (there seem to be genetic variations, which exact amino acid chains are used by the body to produce the enzyme), but I would be surprised if the differences were anything but negligible.
The best I could come up with so far is to assume it's mostly made of Hydrogen and Carbon in a 2:1 ratio and then use its molecular mass (55,4 kDa) to calculate the number of Atoms (55400/14*3=11871). Now considering that other atoms in the molecule are certain to be heavier, I'd say roughly 11000 would be a fair guess.
Am I close or way off. Or is there a better solution?