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Teresa Requena - One of the best experts on this subject based on the ideXlab platform.
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enzymatic ability of bifidobacterium animalis subsp lactis to hydrolyze milk proteins identification and characterization of endopeptidase o
Applied and Environmental Microbiology, 2005Co-Authors: C Janer, Fabrizio Arigoni, Byonghoon Lee, Carmen Pelaez, Teresa RequenaAbstract:The proteolytic system of Bifidobacterium animalis subsp. lactis was analyzed, and an intracellular endopeptidase (PepO) was identified and characterized. This work reports the first complete cloning, purification, and characterization of a proteolytic enzyme in Bifidobacterium spp. Aminopeptidase activities (general Aminopeptidases, proline iminopeptidase, X-prolyl dipeptidylAminopeptidase) found in cell extracts of B. animalis subsp. lactis were higher for cells that had been grown in a milk-based medium than for those grown in MRS. A high specific proline iminopeptidase activity was observed in B. animalis subsp. lactis. Whole cells and cell wall-bound protein fractions showed no caseinolytic activity; however, the combined action of intracellular proteolytic enzymes could hydrolyze casein fractions rapidly. The endopeptidase activity of B. animalis subsp. lactis was examined in more detail, and the gene encoding an endopeptidase O in B. animalis subsp. lactis was cloned and overexpressed in Escherichia coli. The deduced amino acid sequence for B. animalis subsp. lactis PepO indicated that it is a member of the M13 peptidase family of zinc metallopeptidases and displays 67.4% sequence homology with the predicted PepO protein from Bifidobacterium longum. The recombinant enzyme was shown to be a 74-kDa monomer. Activity of B. animalis subsp. lactis PepO was found with oligopeptide substrates of at least 5 amino acid residues, such as met-enkephalin, and with larger substrates, such as the 23-amino-acid peptide alpha s1-casein(f1-23). The predominant peptide bond cleaved by B. animalis subsp. lactis PepO was on the N-terminal side of phenylalanine residues. The enzyme also showed a post-proline secondary cleavage site.
Richard J Fitzgerald - One of the best experts on this subject based on the ideXlab platform.
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debittering and hydrolysis of a tryptic hydrolysate of β casein with purified general and proline specific Aminopeptidases from lactococcus lactis ssp cremoris am2
Journal of Food Science, 2001Co-Authors: Paul Bouchier, Gerard Ocuinn, Dermot Harrington, Richard J FitzgeraldAbstract:In this study, parified β-casein was hydrolysed with trypsin to produce a bitter substrate. The role of 3 Aminopeptidases, a general Aminopeptidase lysyl para-nitroanilide hydrolase (KpNA-H), X-prolyl dipeptidyl Aminopeptidase (Pep X) and Aminopeptidase P (Pep P) each purified from Lactococcus lactis ssp. cremoris AM2, in the hydrolysis and debittering of the tryptic hydrolysate of β-casein, was then studied. The hydrolysates were analyzed for percentage degree of hydrolysis (DH%) and bitterness score. Results indicate that the hydrolysis and debittering potential of the general Aminopeptidase (KpNA-H) is limited in the absence of proline specific Aminopeptidases. Statistically significant (p L'hydrolyse des proteines du lait peut, dans certaines conditions, permettre l'amelioration des proprietes des proteines. Cependant, associee a l'hydrolyse des proteines, une saveur amere peut se developper due a des peptides contenant des residus d'acides amines hydrophobes. Cette etude caracterise la desamerisation potentielle par des Aminopeptidases, a large specificite et specifiques de la proline, isolees de Lactococcus lactis ssp. cremoris AM2, sur un hydrolysat de β-caseine bovine. Les resultats indiquent que l'hydrolyse et la desamerisation par l'Aminopeptidase generale est limitee en l'absence de l'Aminopeptidase specifique. Des reductions specifiques d'amertume sont observees apres incubation de l'hydrolysat tryptique de β-caseine avec la combinaison des 2 Aminopeptidases.
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debittering of a tryptic digest of bovine p casein using porcine kidney general Aminopeptidase and x prolydipeptidyl Aminopeptidase from lactococcus lactis subsp cremoris am2
Journal of Food Science, 2000Co-Authors: C M Barry, Gerard Ocuinn, Dermot Harrington, D M Ocallaghan, Richard J FitzgeraldAbstract:: The role of leucine Aminopeptidase (LAP) from pig kidney cytosol and X-prolyldipeptidyl Aminopeptidase (Pep X) from Lactococcus lactis subsp. cremoris AM2 in the hydrolysis and debittering of a tryptic digest of β-casein was studied. Hydrolysis was monitored by quantifying the release of primary amino groups and bitterness by use of a trained sensory panel. Sequential incubation of the bitter tryptic hydrolysate with LAP, Pep X and LAP resulted in higher levels of hydrolysis and significantly (P < 0.001) lower levels of bitterness than incubation with LAP alone. The results demonstrate the central role proline-specific Aminopeptidases can play in the hydrolysis and debittering of food protein hydrolysates.
Nigel M. Hooper - One of the best experts on this subject based on the ideXlab platform.
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Inhibition by Converting Enzyme Inhibitors of
2016Co-Authors: Pig Kidney Aminopeptidase P, John Hryszko, Nigel M. Hooper, A J TurnerAbstract:Several inhibitors of angiotensin converting enzyme were also found to inhibit Aminopeptidase P, whereas inhibitors of other mammalian Aminopeptidases were ineffective. Aminopeptidase P purified from pig kidney cortex was found to contain one atom of zinc per polypeptide chain, confirming its metalloenzyme nature. The concentrations of converting enzyme inhibitors required to cause 50 % inhibition (I50) of Aminopeptidase P were in the low micromolar range. The most potent converting enzyme inhibitors toward Aminopeptidase P were the carboxylalkyl compounds, cilazaprilat, enalaprilat, and ramiprilat (I50 values of 3-12 /iM). The sulfydryl compounds captopril (l50 110 /iM) and YS980 (I50 20 /iM) were slightly less potent at inhibiting Aminopeptidase P. In contrast, the carboxylalkyl compounds benazeprilat, lisinopril, and pentoprilat; the sulfydryl compound rentiapril; and the phosphoryl compounds ceranopril and fosinoprilat had no inhibitory effect against Aminopeptidase P. This compares with I50 values in the 1-6 nM range for these inhibitors with angiotensin converting enzyme. Inhibition of Aminopeptidase P may account for some of the effects or side effects noted with the clinical use of converting enzyme inhibitors. These results may provide the basis for the design of more selective inhibitors of angiotensin converting enzyme or mixed inhibitors of Aminopeptidase P and angiotensin converting enzyme, or both. (Hypertension 1992;19:281-285
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Inhibition of Aminopeptidases N, A and W: A re-evaluation of the actions of bestatin and inhibitors of angiotensin converting enzyme
Biochemical pharmacology, 1992Co-Authors: Stephen Tieku, Nigel M. HooperAbstract:The effects of a range of metallopeptidase inhibitors on the activities of the porcine kidney cell surface zinc Aminopeptidases, Aminopeptidase A (AP-A; EC 3.4.11.2), Aminopeptidase N (AP-N; EC 3.4.11.7) and Aminopeptidase W (AP-W; EC 3.4.11.16), have been directly compared. Amastatin and probestin were effective against all three Aminopeptidases, with the concentration of inhibitor required to cause 50% inhibition (I50) in the low micromolar range (I50 = 1.5-20 microM), except for probestin with AP-N which displayed an I50 of 50 nM. Actinonin failed to inhibit significantly either AP-A or AP-W, and thus can be considered a relatively selective inhibitor (I50 = 2.0 microM) of AP-N. In contrast, bestatin was a relatively poor inhibitor of AP-N (I50 = 89 microM) and failed to inhibit AP-A, but was more potent towards AP-W (I50 = 7.9 microM). Thus, some of the observed chemotherapeutic actions of bestatin may be due to inhibition of cell-surface AP-W. A number of other metallopeptidase inhibitors, including inhibitors of endopeptidase-24.11 (EC 3.4.24.11) and membrane dipeptidase (EC 3.4.13.11), and the carboxylalkyl and phosphoryl inhibitors of angiotensin converting enzyme (EC 3.4.15.1) failed to inhibit significantly AP-A, AP-N or AP-W. However, AP-W was inhibited with I50 values in the micromolar range by the sulphydryl converting enzyme inhibitors rentiapril (I50 = 1.6 microM), zofenoprilat (I50 = 7.0 microM) and YS 980 (I50 = 17.7 microM). Neither AP-A nor AP-N were affected by these sulphydryl compounds. Inhibition of AP-W may account for some of the side effects noted with the clinical use of the sulphydryl converting enzyme inhibitors. The availability of compounds which are totally selective for AP-W over any of the other mammalian cell surface zinc Aminopeptidases may aid in identifying endogenous substrates, and thus physiological or pathophysiological role(s) of AP-W.
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inhibition by converting enzyme inhibitors of pig kidney Aminopeptidase p
Hypertension, 1992Co-Authors: Nigel M. Hooper, John Hryszko, Sylvester Y Oppong, A J TurnerAbstract:Several inhibitors of angiotensin converting enzyme were also found to inhibit Aminopeptidase P, whereas inhibitors of other mammalian Aminopeptidases were ineffective. Aminopeptidase P purified from pig kidney cortex was found to contain one atom of zinc per polypeptide chain, confirming its metalloenzyme nature. The concentrations of converting enzyme inhibitors required to cause 50% inhibition (I50) of Aminopeptidase P were in the low micromolar range. The most potent converting enzyme inhibitors toward Aminopeptidase P were the carboxylalkyl compounds, cilazaprilat, enalaprilat, and ramiprilat (I50 values of 3-12 microM). The sulfhydryl compounds captopril (I50 110 microM) and YS980 (I50 20 microM) were slightly less potent at inhibiting Aminopeptidase P. In contrast, the carboxylalkyl compounds benazeprilat, lisinopril, and pentoprilat; the sulfhydryl compound rentiapril; and the phosphoryl compounds ceranopril and fosinoprilat had no inhibitory effect against Aminopeptidase P. This compares with I50 values in the 1-6 nM range for these inhibitors with angiotensin converting enzyme. Inhibition of Aminopeptidase P may account for some of the effects or side effects noted with the clinical use of converting enzyme inhibitors. These results may provide the basis for the design of more selective inhibitors of angiotensin converting enzyme or mixed inhibitors of Aminopeptidase P and angiotensin converting enzyme, or both.
A J Turner - One of the best experts on this subject based on the ideXlab platform.
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Inhibition by Converting Enzyme Inhibitors of
2016Co-Authors: Pig Kidney Aminopeptidase P, John Hryszko, Nigel M. Hooper, A J TurnerAbstract:Several inhibitors of angiotensin converting enzyme were also found to inhibit Aminopeptidase P, whereas inhibitors of other mammalian Aminopeptidases were ineffective. Aminopeptidase P purified from pig kidney cortex was found to contain one atom of zinc per polypeptide chain, confirming its metalloenzyme nature. The concentrations of converting enzyme inhibitors required to cause 50 % inhibition (I50) of Aminopeptidase P were in the low micromolar range. The most potent converting enzyme inhibitors toward Aminopeptidase P were the carboxylalkyl compounds, cilazaprilat, enalaprilat, and ramiprilat (I50 values of 3-12 /iM). The sulfydryl compounds captopril (l50 110 /iM) and YS980 (I50 20 /iM) were slightly less potent at inhibiting Aminopeptidase P. In contrast, the carboxylalkyl compounds benazeprilat, lisinopril, and pentoprilat; the sulfydryl compound rentiapril; and the phosphoryl compounds ceranopril and fosinoprilat had no inhibitory effect against Aminopeptidase P. This compares with I50 values in the 1-6 nM range for these inhibitors with angiotensin converting enzyme. Inhibition of Aminopeptidase P may account for some of the effects or side effects noted with the clinical use of converting enzyme inhibitors. These results may provide the basis for the design of more selective inhibitors of angiotensin converting enzyme or mixed inhibitors of Aminopeptidase P and angiotensin converting enzyme, or both. (Hypertension 1992;19:281-285
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inhibition by converting enzyme inhibitors of pig kidney Aminopeptidase p
Hypertension, 1992Co-Authors: Nigel M. Hooper, John Hryszko, Sylvester Y Oppong, A J TurnerAbstract:Several inhibitors of angiotensin converting enzyme were also found to inhibit Aminopeptidase P, whereas inhibitors of other mammalian Aminopeptidases were ineffective. Aminopeptidase P purified from pig kidney cortex was found to contain one atom of zinc per polypeptide chain, confirming its metalloenzyme nature. The concentrations of converting enzyme inhibitors required to cause 50% inhibition (I50) of Aminopeptidase P were in the low micromolar range. The most potent converting enzyme inhibitors toward Aminopeptidase P were the carboxylalkyl compounds, cilazaprilat, enalaprilat, and ramiprilat (I50 values of 3-12 microM). The sulfhydryl compounds captopril (I50 110 microM) and YS980 (I50 20 microM) were slightly less potent at inhibiting Aminopeptidase P. In contrast, the carboxylalkyl compounds benazeprilat, lisinopril, and pentoprilat; the sulfhydryl compound rentiapril; and the phosphoryl compounds ceranopril and fosinoprilat had no inhibitory effect against Aminopeptidase P. This compares with I50 values in the 1-6 nM range for these inhibitors with angiotensin converting enzyme. Inhibition of Aminopeptidase P may account for some of the effects or side effects noted with the clinical use of converting enzyme inhibitors. These results may provide the basis for the design of more selective inhibitors of angiotensin converting enzyme or mixed inhibitors of Aminopeptidase P and angiotensin converting enzyme, or both.
C Janer - One of the best experts on this subject based on the ideXlab platform.
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enzymatic ability of bifidobacterium animalis subsp lactis to hydrolyze milk proteins identification and characterization of endopeptidase o
Applied and Environmental Microbiology, 2005Co-Authors: C Janer, Fabrizio Arigoni, Byonghoon Lee, Carmen Pelaez, Teresa RequenaAbstract:The proteolytic system of Bifidobacterium animalis subsp. lactis was analyzed, and an intracellular endopeptidase (PepO) was identified and characterized. This work reports the first complete cloning, purification, and characterization of a proteolytic enzyme in Bifidobacterium spp. Aminopeptidase activities (general Aminopeptidases, proline iminopeptidase, X-prolyl dipeptidylAminopeptidase) found in cell extracts of B. animalis subsp. lactis were higher for cells that had been grown in a milk-based medium than for those grown in MRS. A high specific proline iminopeptidase activity was observed in B. animalis subsp. lactis. Whole cells and cell wall-bound protein fractions showed no caseinolytic activity; however, the combined action of intracellular proteolytic enzymes could hydrolyze casein fractions rapidly. The endopeptidase activity of B. animalis subsp. lactis was examined in more detail, and the gene encoding an endopeptidase O in B. animalis subsp. lactis was cloned and overexpressed in Escherichia coli. The deduced amino acid sequence for B. animalis subsp. lactis PepO indicated that it is a member of the M13 peptidase family of zinc metallopeptidases and displays 67.4% sequence homology with the predicted PepO protein from Bifidobacterium longum. The recombinant enzyme was shown to be a 74-kDa monomer. Activity of B. animalis subsp. lactis PepO was found with oligopeptide substrates of at least 5 amino acid residues, such as met-enkephalin, and with larger substrates, such as the 23-amino-acid peptide alpha s1-casein(f1-23). The predominant peptide bond cleaved by B. animalis subsp. lactis PepO was on the N-terminal side of phenylalanine residues. The enzyme also showed a post-proline secondary cleavage site.