This biosynthesis is noteworthy because plant biosyntheses employing cinnamic acid as a starting point are rare compared to the more common use of p-coumaric acid.
12.
A 2013 study found that " p "-Coumaric acid, which is normally present in honey, assists bees in detoxifying certain pesticides.
13.
It is found in " Brettanomyces bruxellensis ", a yeast responsible of the presence of ethyl phenols in wine formed from p-coumaric acid.
14.
It is found in the rumen of sheep fed with dried grass and is produced by hydrogenation of the 2-propenoic side chain of p-coumaric acid.
15.
Phloretic acid is found in the rumen of sheep fed with dried grass and is produced by hydrogenation of the 2-propenoic side chain of p-coumaric acid.
16.
Some plants, mainly monocotyledonous, use tyrosine to synthesize p-coumaric acid by the action of the bifunctional enzyme Phenylalanine / tyrosine ammonia-lyase ( PTAL ).
17.
The para position of the ring is then hydroxylated by the cytochrome P450 enzyme cinnamate 4-hydroxylase ( C4H / P450 ) to create " p "-coumaric acid.
18.
The enzyme 4-hydroxycinnamate decarboxylase, induced in bacteria species such as " Klebsiella oxytoca ", works also with p-coumaric acid analogs such as E-2, 4-dihydroxycinnamic acid.
19.
There are many other acids in small quantities : citric acid, ascorbic acid, ?-ketoglutaric, fumaric acid, galacturonic acid, coumaric acid, etc . Their variable quantity varies the pH of the wort.
20.
The 4-coumaric acid is again hydroxylated by cinnamate / coumarate 2-hydroxylase to yield 2, 4-dihydroxy-cinnamic acid followed by a bond rotation of the unsaturated bond adjacent to the carboxylic acid group.
