ACh is a neurotransmitter and Neuropeptide. It is not like Epinephrine and Norepinephrine which are both hormones and N.transmitter.
Neither are enzymes as they do not increase a rate of reaction of anything, nor do they change any mechanism or pathway systems.
Denaturation only affects H-Bond between molecules. ACh is a polypeptide and its units are made by peptide bond. Its member do not hydrogen bond so much in normal body PH, so denaturation agent does not have much effect on it.