Hippuryl histidyl leucine

Crude ACE was isolated according to the reported literature [44 (link)]. Hippuryl-histidyl-leucine (HHL; ≥99%) and ACE (from rabbit lung) were purchased from Sigma Chemical Co. (St. Louis, MO, USA). 2-MeIM (≥99%), DA (≥99%) and HPLC-grade trifluoroacetic acid were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). DA-PEGx-DA (x = 2000, 5000 and 10,000) were purchased from Guangzhou Tansh-tech Co., Ltd. (Guangzhou, China). VPP and GF-6 were obtained from GL Biochem (Shanghai) Ltd. (Shanghai, China). HPLC-grade methanol and acetonitrile were purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). All the other reagents were of analytical grade and purchased from XiLong Science (Guangdong, China).

Chloroform, acetone, and acetonitrile (CAN) were purchased from Biosolve (Dieuze, France), methanol was obtained from Carlo Erba Reagent (Carlo Erba Reagent, Val-de-Reuil, France), ammonia was purchased from EMSURE (Fontnay-Sous-Bois, France), trifluoroacetic acid (TFA) was supplied by Thermo Fisher Scientific (Waltham, MA, USA). Alcalase^® 2.4 L from Bacillus licheniformis, Neutrase^® 0.8 L from Bacillus amyloliquefaciens, hexane, boron trifluoride-methanol solution, hippuryl histidyl-leucine (HHL), 2-(cyclohexylamino)ethanesulfonic acid (CHES), (ethylenediamino) tetraacetic acid (EDTA), angiotensin converting enzyme (ACE) derived from rabbit lung, C23, and all HPLC standards were purchased from Sigma-Aldrich (Munich, Germany). All other reagents used in this study were of analytical grade.

Camellia seeds were purchased from Quzhou City, Zhejiang Province. Angiotensin I-converting enzyme (ACE) from rabbit lungs (0.1 U) (Table A1), ACE substrate hippuryl-histidyl-leucine (HHL) and hippuric acid (HA) standards were purchased from Sigma-Aldrich (St. Louis, MO, USA). Neutral protease (50,000 U/g), alkaline protease (200,000 U/g), papain (800,000 U/g), trypsin (250,000 U/g), and Sephadex G-25 were purchased from Beijing Solarbio Science & Technology Co., Ltd. (Beijing, China). All other chemicals used were of analytical grade.

Alcalase^® 2.4 L (from Bacillus licheniformis), Pancreatic Trypsin Novo 6.0S, Protease type XIV, also known as Pronase E (from Streptomyces griseus) and Esperase^® 8.0 L (from Bacillus spp.) were obtained from Novozymes (Bagsværd, Denmark). Angiotensin-Converting Enzyme I (ACE, EC 3.4.15.1), aprotinin, vitamin B12, angiotensin II, hippuryl histidyl leucine (HHL) and glycine were obtained from Sigma Chemical Co., (St. Louis, MO, USA). Abz-GLY-PHe(NO₂)-Pro was obtained from Bachem Feinchemikalien (Bubendorf, Switzerland). All other chemicals and reagents used were of analytical grade and were purchased from Panreac Chemical Corp. (Barcelona, Spain).

ACE from rabbit lung and hippuryl‐histidyl‐leucine (HHL) were sourced from Sigma Chemical Co. (St. Louis). Captopril, acetonitrile of HPLC grade, and trifluoroacetic acid (TFA) were obtained from Macklin Biochemical Co. All other reagents were of analytical grade.

Fresh bighead carp backbones were cut into segments of about 6 cm and stored at −20 °C. Frozen backbones were thawed at 10 °C before use. Flavourzyme was purchased from Novozyme (Tianjin, China). Cytochrome C, aprotinin, bacitracin and hippuryl-histidyl-leucine (HHL) were obtained from Sigma-Aldrich (Milwaukee, WI, USA). Further, 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) diammonium salt and 1,1-diphenyl-2-picrylhydrazy (DPPH) were obtained from Aladdin Reagents Co., Ltd. (Shanghai, China). Acetonitrile (ACN) and trifluoroacetic acid (TFA) were of chromatographical grade. All the other chemicals were of analytical grade and were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China).

Wild jujube seeds (Ziziphus jujuba Mill.var.spinosa (Bunge) HuexH.F. Chou) were obtained from the Jilin Hospital of Traditional Chinese Medicine, and the seeds were originated from Shanxi province of China.
DPPH, 2,2′‐azinobis‐(3‐ethylbenzthiazoline‐6‐sulfonate) (ABTS⁺), and ACE were obtained from Beijing Solarbio Science & Technology Co., Ltd. (Beijing, China). Alcalase, neutrase, papain, and hippuric acid (HA) were obtained from Shanghai Yuanye Bio‐Technology Co., Ltd. (Shanghai, China). 2′, 7′‐ Dichlorodihydrofluorescein diacetate (DCFH‐DA) was purchased from Beyotime Biotechnology Co., Ltd. (Shanghai, China). Malondialdehyde (MDA), glutathione peroxidase (GSH‐Px), and superoxide dismutase (SOD) test kits were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, China). Hippuryl‐histidyl‐leucine (HHL) was purchased from Sigma Chemical Company (St. Louis, MO, USA). Other reagents and chemicals were of analytical grade.