L phenylalanine

Ethanol, sodium carbonate (Na₂CO₃), Disodium hydrogenorthophosphate, sodium dihydrogen phosphate, 30% hydrogen peroxide, Vit C, catechol, 2-methoxyphenol, β-mercaptoEthanol, polyvinylpyrrolidone (PVPP), glycerol, tris-base, hydrochloric acid, and magnesium chloride (MgCl₂) were obtained from Tianjin Kemiou Chemical Reagent Co., Ltd. (Tianjin, China). Folin–Ciocalteu reagent, potassium persulfate, leupeptin, phenylmethylsulfonyl fluoride, boracic acid, borax, and l-phenylalanine were purchased from Beijing Solarbio Science and Technology CO., Ltd. (Beijing, China). Gallic acid, hydroxybenzoic acid, chlorogenic acid, caffeic acid, sinapic acid, ferulic acid, rutin, cinnamic acid, catechin, and quercetin, were obtained from Shanghai Yuanye Biochemical Co., Ltd. (Shanghai, China). 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azinobis-3-ethylbenzthiazoline-6-sulphonate (ABTS) and adenosine triphosphate were obtained from Shanghai Aladdin Biochemical Co., Ltd. (Shanghai, China). Methyl jasmonate and mEthanol were obtained from Sigma Chemical Co. (St. Louis, MO, USA). MEthanol was reagent of HPLC-grade. The other chemical reagents were of reagent grade.

L-Proline (L-Pro), L-methionine (L-Met), L-valine (L-Val), L-histidine (L-His), L-isoleucine (L-Ile), L-leucine (L-Leu), L-threonine (L-Thr), L-tryptophan (L-Trp), L-tyrosine (L-Tyr), L-alanine (L-Ala), L-serine (L-Ser), L-phenylalanine (L-Phe), L-arginine (L-Arg), L-asparagine (L-Asn), L-aspartic acid (L-Asp), L-cysteine (L-Cys), L-glutamine (L-Gln), L-glutamic acid (L-Glu) and L-lysine (L-Lys) are from Beijing Solarbio Science & Technology Co., Ltd. D-Proline (D-Pro), D-methionine (D-Met),D-leucine (D-Leu) and D-tryptophan (D-Trp) are from Tokyo Chemical Industry Co., Ltd. D-Guanosine is from Beijing Solarbio Since & Technology Co., Ltd. Quinine is from Saen Chemical Technology (Shanghai) Co., Ltd.
Analytical reagents methanol (HPLC grade) was purchased from Spectrum Chemical, and formic acid was purchased from Sigma Aldrich. Ultrapure water from a Heal Force water purification system (Pudong, Shanghai, China) was used to prepare solutions and the mobile phase.
The aa measurements were performed on Jasco-J1700 electronic CD at ambient temperature. The HPLC was performed on Agilent 1260 Infinity system and fitted with an Agilent TC- C18, 5 µm, 4.6 mm × 150 mm column. The column temperature was maintained at room temperature. The HPLC flow rate was 1 ml min⁻¹ with TC-C18.