I may be missing some fantastic resource, but my first thought is to send you to KEGG. Is that crazy? Maybe, but a simple search for Acetyl-CoA in humans can give you tons of useful information, including GO terms, enzymes, genes, and, yes, biochemical reactions; just use the KEGG Pathways tool and specify humans (hsa). You can click on each individual pathway for more information, such as the cholinergic synapse.
!Cholinergic synapse pathway