A042 1 1

Commercial kits were used to determine TG (A110-1-1, Nanjing Jiancheng Bioengineering Institute, Nanjing, China, detection limit: 0–9.04 mmol/L) and NEFA contents (A042-1-1, Nanjing Jiancheng Bioengineering Institute, Nanjing, China, detection limit: 0.01–2.0 mmol/L) according to the manufacturer's instructions, respectively. Phosphorus content of diets and the liver was determined using the molybdovanadate method (spectrophotometry) as described previously (31 (link)). Fatty acid synthase (FAS) activity was measured according to the method of Chang et al. (32 (link)) and Chakrabarty (33 (link)), 6-phosphogluconate dehydrogenase (6PGD) and glucose 6-phosphate dehydrogenase (G6PD) were determined by the method of Barroso et al. (34 (link)), malic enzyme (ME) by Ochoa [Ochoa (35 (link))], isocitrate dehydrogenase (ICDH) according to the method of Bernt and Bergmeyer (36 (link)) and carnitine palmitoyltransferase 1 (CPT1) was analyzed using the method of Bieber and Fiol (37 (link)). The amount of enzyme was defined that converts 1 μM of the substrate to product per minute at 30 °C. The one unit of enzyme activity was expressed as units per milligram of soluble protein, and Bradford Protein Assay Kit (W042-1-1, Nanjing Jiancheng Bioengineering Institute, Nanjing, China, detection limit: 20–2000 μg/ml) was used to determine soluble protein concentration.

Soluble sugar content. The foliar content of soluble sugars in the tested tea leaves was determined using a test kit for plant soluble sugar content (No. A145-1-1; Nanjing Jiancheng Bioengineering Institute, Nanjing, China). The basis for this determination is that when concentrated sulfuric acid solution and sugar are combined, the resulting furfural or hydroxymethyl furfural can react with anthrone, and a change in the absorbance value is formed at 630 nm.
Soluble protein content. The foliar content of soluble sugars in the tea leaves that were tested was determined using a test kit for plant soluble sugar content (No. A145-1-1; Nanjing Jiancheng Bioengineering Institute, Nanjing, China). The anions in Coomassie brilliant blue can react with the amino termini in proteins to turn the solution blue when the dye is added to a sample that contains proteins. The amount of protein in the sample or standard solution can then be determined through measuring the absorbance.
Free fatty acid content. The foliar content of free fatty acids in the tea leaves tested was determined using a free fatty acids assay kit (A042-1-1; Nanjing Jiancheng Bioengineering Institute, Nanjing, China). Free fatty acids can form a copper salt of fatty acids by combining with copper ions and dissolving in chloroform, and a color change occurs.