Final answer:
Histidine Decarboxylase (Hdc) catalyzes the conversion of histidine to histamine.
Step-by-step explanation:
The function of Histidine Decarboxylase (Hdc) is to catalyze the conversion of histidine to histamine. It is an enzyme that removes a carboxyl group from histidine, resulting in the formation of histamine. This conversion is important in various biological processes, including the regulation of blood pressure and the production of certain neurotransmitters.