Thiamine Hydrochloride-13C4 is the 13C labeled compound of Thiamine Hydrochloride. Thiamine Hydrochloride has a CAS number of 67-03-8. Thiamine Hydrochloride is the hydrochloride salt form of thiamine, a vitamin essential for aerobic metabolism, cell growth, transmission of nerve impulses and acetylcholine synthesis. Upon hydrolysis, thiamine hydrochloride is phosphorylated by thiamine diphosphokinase to form active thiamine pyrophosphate (TPP), also known as cocarboxylase. TPP is a coenzyme for many enzymatic activities involving fatty acid, amino acid and carbohydrate metabolism.