Abz gly phe no2 pro

For this research, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 3,4-Dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-carboxylic acid (Trolox), fluorescein, 2,2′-diazobis-(2-aminodinopropane)-dihydrochloride (AAPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Fe(III) chloride, 2,4,6-tri (2-pyridyl)-s-triazine (TPTZ), ferrozine, Folin–Ciocalteu reagent, gallic acid (GA), angiotensin-converting enzyme from rabbit lung, human dipeptidyl peptidase-IV and reagents used in HPLC analysis were obtained from Sigma-Aldrich, Co. (St. Louis, MO, USA). The prolyl endopeptidase from Flavobacterium was from Seikagaku Corp. (Tokyo, Japan). The chromogenic substrates (Abz-Gly-Phe(NO2)-Pro) and (Z-Gly-Pro-7-amido-4-methylcoumarin) were from Bachem (Bubendorf, Switzerland). Ethylenediaminetetraacetic acid (EDTA) was from Leco Corp. (St. Joseph, MI, USA). Other chemicals and reagents of analytical grade were obtained from Panreac Chemical Co. (Barcelona, Spain).

Three Lactobacillus strains were used in this study: L. helveticus 45a, L. helveticus 49d, and L. helveticus 60b. These strains were previously isolated from different Mongolian dairy products based on their proteolytic abilities (Raveschot et al., 2020 (link)).
Maltodextrin (Glucidex IT 12) was obtained from Roquette (Lestrem, France). The fluorescent substrate for ACE (Abz-Gly-Phe(NO₂)-Pro) was purchased from Bachem (Bubendorf, Switzerland). Finally, skim milk powder and all other reagents were purchased from Sigma-Aldrich (St. Louis, MO, United States).

The enzymes used for microalgae hydrolysis, cellulase (New Cell Supreme 4000L) and subtilisin (a protease) (New Pro 16L), were supplied by Aquitex. The microalga was provided by Allmicroalgae-Natural Products, S.A (Pataias, Alcobaça). Sulfuric acid and Kjeldahl tablets (catalyst with 0.3% CuSO4 5H₂O) were purchased from VWR Scientific (VWR chemicals, Karlsruhe, Germany); boric acid and hydrochloric acid (32%) were purchased from Merck (Darmdstadt, Germany); sodium hydroxide was purchased from LabChem (Zelienople, PA, USA). The proteins standard used (thyroglobulin, ferritin, aldolase, conalbumin, ovalbumin, carbonic anhydrase, ribonuclease A, and aprotinin) were acquired from GE Healthcare (Milwaukee, WI, USA), and the peptide KGYGGVSLPEW was obtained from GenScript (Nanjing, China).
Regarding the bioactivities, fluorescein, 2,2′-azo-bis-(2-methylpropionamidine)-dihydrochloride (≥97%), 6-hydroxy-2,5,7,8-tetramethylbroman-2-carboxylic acid (Trolox) (≥97%), angiotensin I-converting enzyme (EC 3.4.15.1, 5.1 U mg⁻¹), and α-glucosidase (EC 3.2.1.20) were acquired from Sigma-Aldrich (St. Louis, MO, USA), while Abz–Gly–Phe (NO₂)–Pro was supplied by Bachem Feinchemikalien (Bubendorf, Switzerland).