Casein Fermentate of Lactobacillus animalis DPC6134 Contains a Range of Novel Propeptide Angiotensin-Converting Enzyme Inhibitors

M Hayes, C Stanton, H Slattery… - Applied and …, 2007 - Am Soc Microbiol
M Hayes, C Stanton, H Slattery, O O'sullivan, C Hill, GF Fitzgerald, RP Ross
Applied and environmental microbiology, 2007Am Soc Microbiol
This work evaluated the angiotensin-converting-enzyme (ACE)-inhibitory activities of a
bovine sodium caseinate fermentate generated using the proteolytic capabilities of the
porcine small intestinal isolate Lactobacillus animalis DPC6134 (NCIMB deposit 41355).
The crude 10-kDa L. animalis DPC6134 fermentate exhibited ACE-inhibitory activity of
85.51%(±15%) and had a 50% inhibitory concentration (IC50) of 0.8 mg protein/ml
compared to captopril, which had an IC50 value of 0.005 mg/ml. Fractionation of the crude L …
Abstract
This work evaluated the angiotensin-converting-enzyme (ACE)-inhibitory activities of a bovine sodium caseinate fermentate generated using the proteolytic capabilities of the porcine small intestinal isolate Lactobacillus animalis DPC6134 (NCIMB deposit 41355). The crude 10-kDa L. animalis DPC6134 fermentate exhibited ACE-inhibitory activity of 85.51% (±15%) and had a 50% inhibitory concentration (IC50) of 0.8 mg protein/ml compared to captopril, which had an IC50 value of 0.005 mg/ml. Fractionation of the crude L. animalis DPC6134 fermentate by membrane filtration and reversed-phase high-performance liquid chromatography (HPLC) generated three bioactive fractions from a total of 72 fractions. Fractions 10, 19, and 43 displayed ACE-inhibitory activity percentages of 67.53 (±15), 83.71 (±19), and 42.36 (±11), respectively, where ACE inhibition was determined with 80 μl of the fractions with protein concentrations of 0.5 mg/ml. HPLC and mass spectrometry analysis identified 25 distinct peptide sequences derived from α-, β-, and κ-caseins. In silico predictions, based on the C-terminal tetrapeptide sequences, suggested that peptide NIPPLTQTPVVVPPFIQ, corresponding to β-casein f(73-89); peptide IGSENSEKTTMP, corresponding to αs1-casein f(201212); peptide SQSKVLPVPQ, corresponding to β-casein f(166-175); peptide MPFPKYPVEP, corresponding to β-casein f(124133); and peptide EPVLGPVRGPFP, corresponding to β-casein f(210-221), contained ACE-inhibitory activities. These peptides were chosen for chemical synthesis to confirm the ACE-inhibitory activity of the fractions. Chemically synthesized peptides displayed IC50 values in the range of 92 μM to 790 μM. Additionally, a simulated gastrointestinal digestion confirmed that the ACE-inhibitory 10-kDa L. animalis DPC6134 fermentation was resistant to a cocktail of digestive enzymes found in the gastrointestinal tract.
American Society for Microbiology
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