In enzymology, a vanillin synthase (EC 4.1.2.41) is an enzyme that catalyzes the chemical reaction

3-hydroxy-3-(4-hydroxy-3-methoxyphenyl)propanoyl-CoA ${\displaystyle \rightleftharpoons }$ vanillin + acetyl-CoA

Hence, this enzyme has one substrate, 3-hydroxy-3-(4-hydroxy-3-methoxyphenyl)propanoyl-CoA, and two products, vanillin and acetyl-CoA.

This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is 3-hydroxy-3-(4-hydroxy-3-methoxyphenyl)propanoyl-CoA vanillin-lyase (acetyl-CoA-forming). Other names in common use include 3-hydroxy-3-(4-hydroxy-3-methoxyphenyl)propionyl-CoA:vanillin lyase, and (acetyl-CoA-forming).

• Narbad A, Gasson MJ. "Metabolism of ferulic acid via vanillin using a novel CoA-dependent pathway in a newly-isolated strain of Pseudomonas fluorescens". Microbiology. 144 (5): 1397–1405. doi:10.1099/00221287-144-5-1397. PMID 9611814.
• Pometto AL 3rd, Crawford DL (1983). "Whole-cell bioconversion of vanillin to vanillic acid by Streptomyces viridosporus". Appl. Environ. Microbiol. 45 (5): 1582–1585. PMC 242504. PMID 6870241.