nicotinamidase
Nicotinamidase is an enzyme that catalyzes the hydrolysis of nicotinamide (also known as niacinamide or vitamin B3) to nicotinic acid (niacin). This reaction is a crucial step in the metabolism of vitamin B3 in many organisms. The enzyme belongs to the amidohydrolase family and is characterized by its ability to specifically cleave the amide bond of nicotinamide. Nicotinamidase plays a role in vitamin B3 salvage pathways, allowing organisms to convert ingested or produced nicotinamide into nicotinic acid, which can then be utilized in various metabolic processes, most notably as a precursor to NAD+ and NADP+.
The enzyme has been identified in a wide range of organisms, including bacteria, fungi, plants, and mammals.