Characterization, development and localization of "flavanone synthase" in tulip anthers.

2. p-Coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA were found to be efficient substrates of the synthase. The products formed were naringenin (5,7,4'-trihydroxyflavanone), eriodictyol (5,7,3',4'-tetrahydroxyflavanone) and homoeriodictyol (5,7,4'-trihydroxy-3'-methoxyflavanone), re­ spectively. Addition of thiol reagents at concentrations exceeding 10~ 3 m caused inhibition of the enzyme. “Release products”, however, were not detectable. Although exclusively chalcones accumu­ late in the tulip anther, only flavanones but no chalcones were detectable in our in vitro system.