title: Angiotensin I-converting enzyme inhibitory proteins and peptides from the rhizomes of Zingiberaceae plants.
abstract: Ammonium sulphate cut protein extracts, and their pepsin hydrolysates, from the rhizomes of 15 plants in the Zingiberaceae family were screened for their in vitro angiotensin I-converting enzyme inhibitory (ACEI) activity. The protein extract from Zingiber ottensii had the highest ACEI activity (IC(50) of 7.30 × 10(-7) mg protein/mL) and was enriched for by SP Sepharose chromatography with five NaCl step gradients 0, 0.25, 0.50, 0.75 and 1 M NaCl collecting the corresponding five fractions. The highest ACEI activity was found in the F75 fraction, which appeared to contain a single 20.7-kDa protein, suggesting enrichment to or near to homogeneity. The ACEI activity of the F75 fraction was moderately thermostable (-20-60 °C), showed >80% activity across a broad pH range of 4-12 (optimal at pH 4-5) and appeared as a competitive inhibitor of ACE (K(i) of 9.1 × 10(-5) mg protein/mL). For the pepsin hydrolysates, that from Zingiber cassumunar revealed the highest ACEI activity (IC(50) of 0.38 ± 0.012 mg/mL), was enriched to a single active hexapeptide by RP-HPLC with a strong ACEI activity (IC(50) of 0.011 ± 0.012 mg/mL) and acted as a competitive inhibitor of ACE (K(i) of 1.25 × 10(-6) mg protein/mL).
authors.affiliation: Program in Biotechnology, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
authors.forename: Maneerat
authors.initials: M
authors.lastname: Yodjun
authors.forename: Aphichart
authors.initials: A
authors.lastname: Karnchanatat
authors.forename: Polkit
authors.initials: P
authors.lastname: Sangvanich
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D027343:Rhizome / Q000737:chemistry*; D013696:Temperature; D030521:Zingiberaceae / Q000737:chemistry*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D010446:Peptide Fragments; D010940:Plant Proteins; D007703:Peptidyl-Dipeptidase A; D010434:Pepsin A