Involved in the biosynthesis of volatile esters which confer ripe apple fruit flavor (PubMed:24661745). Alcohol acyl transferase that can use a wide range of alcohols as substrate, including 2-methylbutanol, hexanol and ethanol, to produce esters such as butyl butanoate, butyl hexanoate, hexyl butanoate, ethyl butanoate and ethyl hexanoate and, to some extent, 2-methylbutyl acetate (2MBA), butyl acetate, hexyl acetate and 2-methylbutyl butanoate (2MBB) (PubMed:24661745). acetyl-CoA + butan-1-ol = butyl acetate + CoA butan-1-ol + butanoyl-CoA = butyl butanoate + CoA butan-1-ol + hexanoyl-CoA = butyl hexanoate + CoA butanoyl-CoA + hexan-1-ol = CoA + hexyl butanoate acetyl-CoA + hexan-1-ol = CoA + hexyl acetate 2-methylbutan-1-ol + butanoyl-CoA = 2-methylbutyl butanoate + CoA butanoyl-CoA + ethanol = CoA + ethyl butanoate ethanol + hexanoyl-CoA = CoA + ethyl hexanoate Highly expressed in the cortex and skin of ripe fruit. Accumulates progressively during fruit development, but fades out in ripe fruit. The fruit of cv. Royal Gala exhibits a high ester accumulation, whereas the cv. Granny Smith contains low ester levels; this influences strongly the ripe apple fruit aroma. Belongs to the plant acyltransferase family. The intimacy of flavour - Issue 231 of December 2020