ethanethiol + 2-aminoprop-2-enoate => S-ethyl-L-cysteine
ethanethiol + 2-aminoprop-2-enoate => s-ethyl-l-cysteine
ethanethiol + 2-aminoprop-2-enoate => S-ethyl-L-cysteine
ethanethiol + 2-aminoprop-2-enoate => s-ethyl-l-cysteine