Enzyme assay
Extract preparation
All enzyme extract procedures were conducted at 4 °C.
Frozen leaf tissues (2 g) were ground with 10 ml
extracting buffer (0.2 M boric acid buffer, containing
1 mM EDTA and 50 mM b-mercaptoethanol, pH 8.8).
The extracts were homogenised and centrifuged at12 000 9 g at 4 °C for 30 min, and the supernatant
was collected.
Enzyme assay
Tyrosine ammonia-lyase (TAL) assay. Tyrosine ammonia-
lyase activity was performed according to Abdel-
Fattah & Al-Amri (2012). Specific enzyme activity was
defined as mM p-coumaric acid per minute per mg of
protein.