N hippuryl his leu hydrate

Live shrimp (L. vannamei) (20.3 ± 0.7 g in weight, 12.2 ± 0.3 cm in length, and about three months old) were obtained from the local aquaculture base of Zhanjiang Guolian Fisheries Co., Ltd. The shrimp were transported to the laboratory in oxygen flushing seawater tank within approximately 1 hr. Upon arrival, the shrimp were washed with clean water and beheaded and the heads were collected. The collected shrimp heads stored in an ultralow temperature freezer at −75 ℃ prior to use.
MW standards (e.g., triosephosphate isomerase [26,625 Da], myoglobin [16,950 Da], α‐lactalbumin [14,437 Da], aprotinin [6,512 Da], oxidized insulin b chain [3,496 Da]), and bacitracin (1,423 Da) were obtained from Bio‐Rad. N‐Hippuryl‐His‐Leuhydrate (429.47 Da) was procured from Sigma‐Aldrich.

Hesperidin, hesperetin, narirutin, naringenin, DPPH, 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), ferrous sulfate heptahydrate, fluorescein sodium salt, N-hippuryl-his-leu hydrate (HHL), lung acetone powder from rabbit, xanthine oxidase from bovine milk, allopurinol, ρ-nitrophenyl-β-D-glucopyranoside (ρ-NPG), acarbose, α-glucosidase from Saccharomyces cerevisiae, ρ-nitrophenyl butyrate (ρ-NPB), lipase from porcine pancreas, orlistat, and 3-(N-Morpholino)propane sulfonic acid (MOPS) were purchased from Sigma Chemical Co. (St. Louis, MO). 2,2′-Azobis(2-methylpropionamidine) dihydrochloride (AAPH) was purchased from Acros organics (Geel, Belgium) and captopril was purchased from Tokyo Chemical Industry Co., Ltd. (Kita-ku, Tokyo, Japan). Sinensetin, nobiletin, and tangeretin were purchased from Avention (Yeonsu-gu, Incheon, Korea). hesperetin-7-O-glucoside and prunin were purchased from Extrasynthese (Genay, France). Acetic acid was purchased from Junsei Chemical Co., Ltd (Chuo-ku, Tokyo, Japan) and HPLC grade acetonitrile and methyl alcohol were purchased from Daejung Chemicals & Metals Co., Ltd (Shiheung, Gyeonggi, Korea).

DPPH, angiotensin-converting enzyme (0.25 U·mL⁻¹, from the rabbit lung), N-hippuryl-His-Leu hydrate (HHL), hippuric acid, and amino acid standards were purchased from Sigma-Aldrich (Shanghai, China). α-Glucosidase protease (50 U/mg, from yeast), α-amylase protease (50 U/mg, from Bacillus subtilis), acarbose, 4-nitrophenyl-β-d-galactopyranoside, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), ribonuclease (13,700 Da, from the bovine pancreas), aprotinin hydrochloride (6511 Da, from the bovine lung), angiotensin II (1046 Da), and l-serine (105 Da) were purchased from Yuanye Biological Technology Co. (Shanghai, China). Trypsin (250 U/mg), pepsin (250 U/mg), Sephadex G25 gel, nifedipine, and vitamin C were purchased from Solarbio (Beijing, China). Transgenic zebrafish Tg (krt4:NTR-hKikGR)^cy17 are maintained in our lab. All chemicals and reagents used for HPLC were of chromatographic grade and other chemicals and reagents were of analytical grade.