Tyrosine Decarboxylase from Streptococcus faecalis (NCTC6783) (Apoenzyme) is primarily used in biochemical research to study the decarboxylation of L-tyrosine to tyramine, a key step in the microbial biosynthesis of biogenic amines, including trace amines like tyramine. This enzyme is valuable for understanding metabolic pathways in amino acid catabolism and the production of these compounds. It is employed in enzymatic assays to quantify tyrosine decarboxylase activity, which is important for studying microbial physiology and diagnosing related metabolic disorders. In the food industry, it aids in monitoring and controlling tyramine levels in fermented products such as cheese, wine, and beer to prevent health risks like tyramine-induced hypertension. Additionally, it serves as a tool in developing biosensors for detecting tyrosine or its derivatives in biological samples.