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Ikeda Z, Kakegawa K, Kikuchi F, Itono S, Oki H, Yashiro H, Hiyoshi H, Tsuchimori K, Hamagami K, Watanabe M, Sasaki M, Ishihara Y, Tohyama K, Kitazaki T, Maekawa T, Sasaki M. Design, Synthesis, and Biological Evaluation of a Novel Series of 4-Guanidinobenzoate Derivatives as Enteropeptidase Inhibitors with Low Systemic Exposure for the Treatment of Obesity. J Med Chem 2022; 65:8456-8477. [PMID: 35686954 PMCID: PMC9234964 DOI: 10.1021/acs.jmedchem.2c00463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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To discover a novel
series of potent inhibitors of enteropeptidase,
a membrane-bound serine protease localized to the duodenal brush border,
4-guanidinobenzoate derivatives were evaluated with minimal systemic
exposure. The 1c docking model enabled the installation
of an additional carboxylic acid moiety to obtain an extra interaction
with enteropeptidase, yielding 2a. The oral administration
of 2a significantly elevated the fecal protein output,
a pharmacodynamic marker, in diet-induced obese (DIO) mice, whereas
subcutaneous administration did not change this parameter. Thus, systemic
exposure of 2a was not required for its pharmacological
effects. Further optimization focusing on the in vitro IC50 value and T1/2, an indicator of dissociation
time, followed by enhanced in vivo pharmacological activity based
on the ester stability of the compounds, revealed two series of potent
enteropeptidase inhibitors, a dihydrobenzofuran analogue ((S)-5b, SCO-792) and phenylisoxazoline (6b), which exhibited potent anti-obesity effects despite their low
systemic exposure following their oral administration to DIO rats.
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Affiliation(s)
- Zenichi Ikeda
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Keiko Kakegawa
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Fumiaki Kikuchi
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Sachiko Itono
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Hideyuki Oki
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Hiroaki Yashiro
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Hideyuki Hiyoshi
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Kazue Tsuchimori
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Kenichi Hamagami
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Masanori Watanabe
- Research Division, SCOHIA PHARMA, Inc., 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Masako Sasaki
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Youko Ishihara
- Pharmaceutical Sciences, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Kimio Tohyama
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Tomoyuki Kitazaki
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Tsuyoshi Maekawa
- Research Division, SCOHIA PHARMA, Inc., 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Minoru Sasaki
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
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Bar-Even A, Milo R, Noor E, Tawfik DS. The Moderately Efficient Enzyme: Futile Encounters and Enzyme Floppiness. Biochemistry 2015. [DOI: 10.1021/acs.biochem.5b00621] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arren Bar-Even
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | | | - Elad Noor
- Institute
of Molecular Systems Biology, ETH Zurich, Auguste-Piccard-Hof 1, CH-8093 Zurich, Switzerland
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Shepherd M, Reid JD, Hunter CN. Purification and kinetic characterization of the magnesium protoporphyrin IX methyltransferase from Synechocystis PCC6803. Biochem J 2003; 371:351-60. [PMID: 12489983 PMCID: PMC1223276 DOI: 10.1042/bj20021394] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2002] [Revised: 11/21/2002] [Accepted: 12/18/2002] [Indexed: 11/17/2022]
Abstract
Magnesium protoporphyrin IX methyltransferase (ChlM), catalyses the methylation of magnesium protoporphyrin IX (MgP) at the C(6) propionate side chain to form magnesium protoporphyrin IX monomethylester (MgPME). Threading methods biased by sequence similarity and predicted secondary structure have been used to assign this enzyme to a particular class of S-adenosyl-L-methionine (SAM)-binding proteins. These searches suggest that ChlM contains a seven-stranded beta-sheet, common among small-molecule methyltransferases. Steady-state kinetic assays were performed using magnesium deuteroporphyrin IX (MgD), a more water-soluble substrate analogue of MgP. Initial rate studies showed that the reaction proceeds via a ternary complex. Product (S-adenosyl-L-homocysteine; SAH) inhibition was used to investigate the kinetic mechanism further. SAH was shown to exhibit competitive inhibition with respect to SAM, and mixed inhibition with respect to MgD. This is indicative of a random binding mechanism, whereby SAH may bind productively to either free enzyme or a ChlM-MgD complex. Our results provide an overview of the steady-state kinetics for this enzyme, which are significant given the role of MgP and MgPME in plastid-to-nucleus signalling and their likely critical role in the regulation of this biosynthetic pathway.
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Affiliation(s)
- Mark Shepherd
- Robert Hill Institute for Photosynthesis, Department of Molecular Biology and Biotechnology, Firth Court, Western Bank, University of Sheffield, Sheffield S10 2TN, UK
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Liu S, Hanzlik RP. The contribution of intermolecular hydrogen bonding to the kinetic specificity of papain. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1158:264-72. [PMID: 8251526 DOI: 10.1016/0304-4165(93)90024-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The binding of substrates to the active site of papain is thought to involve, among other things, intermolecular P1NH-OC(Asp158) and P2NH-OC(Gly66) hydrogen bonding. In this study the contribution of these two putative hydrogen bonds to the interaction specificity of papain was measured for pairs of ligands in which the amide NH in question was either intact or replaced by an ester O linkage. The probe ligands investigated comprised substrates (peptidyl p-nitroanilides), substrate-like transition state analog inhibitors (peptidyl nitriles) and substrate-like affinity labeling agents (peptidyl Michael acceptors). Observed differences in interaction energies (delta delta G(obs) or delta delta G(obs) not equal to) for amide/ester ligand pairs indicated an apparent specificity energy of 2.1-2.6 kcal/mol for the P2NH-OC(Gly66) bond. For the P1NH-OC(Asp158) bond delta delta G(obs) was approx. 1.0 kcal/mol for dipeptidyl ligands but close to zero for ligands lacking a P2NH donor. These specificity energies are comparable to values reported for other enzyme-ligand systems. However, the dependence of delta delta G(obs) for the P1NH-OC(Asp158) bond on the presence of a P2NH donor suggests that these two hydrogen bonds may interact cooperatively in ligand binding. A thermodynamic cycle approach was used to relate delta delta G(obs) to actual hydrogen bond strengths and other aspects of enzyme-ligand and solvent-ligand interactions.
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Affiliation(s)
- S Liu
- Department of Medicinal Chemistry University of Kansas Lawrence 66045-2506
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5
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Brocklehurst K, Topham CM. Some classical errors in the kinetic analysis of enzyme reactions. Biochem J 1993; 295 ( Pt 3):898-9. [PMID: 8240306 PMCID: PMC1134646 DOI: 10.1042/bj2950898] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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6
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Patel M, Kayani IS, Mellor GW, Sreedharan S, Templeton W, Thomas EW, Thomas M, Brocklehurst K. Variation in the P2-S2 stereochemical selectivity towards the enantiomeric N-acetylphenylalanylglycine 4-nitroanilides among the cysteine proteinases papain, ficin and actinidin. Biochem J 1992; 281 ( Pt 2):553-9. [PMID: 1736903 PMCID: PMC1130721 DOI: 10.1042/bj2810553] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. Values of the kinetic specificity constant, kcat./Km, for the hydrolysis of N-acetyl-L-phenylalanylglycine 4-nitroanilide (I) and of its D-enantiomer (II) catalysed by ficin (EC 3.4.22.3) and by actinidin (EC 3.4.22.14) at pH 6.0, I 0.1 mol/l, 8.3% (v/v) NN-dimethylformamide and 25 degrees C were determined by using initial-rate data with [S] much less than Km and weighted nonlinear regression analysis as: for ficin, (kcat./Km)L = 271 +/- 6 M-1.s-1, (kcat./Km)D = 2.9 +/- 0.1 M-1.s-1, and for actinidin (kcat./Km)L = 13.3 +/- 0.7 M-1.s-1, (kcat/Km)D = 0.34 +/- 0.01 M-1.s-1.2. These data and analogous values for the corresponding reactions catalysed by papain (EC 3.4.22.2), (kcat./Km)L = 2064 +/- 31 M-1.s-1, (kcat./Km)D = 5.5 +/- 0.1 M-1.s-1, demonstrate marked variation in stereochemical selectivity for substrates (I) and (II) among the three cysteine proteinases with the following values for the index of stereochemical selectivity Iss = (kcat./Km)L/(kcat./Km)D: for papain, 375; for ficin 93; for actinidin 39. 3. Model building suggests ways in which, for the papain-catalysed reactions, binding interactions involving the extended acyl groups of the substrates may need to change as the reaction proceeds from adsorptive complex (ES) to tetrahedral intermediate (THI) before its rate-determining, general acid-catalysed collapse to acylenzyme intermediate. In particular, satisfactory alignment in the catalytic site at the THI stage of the acylation process appears to demand rotation of the substrate moiety about its long axis. 4. The different consequences of this rotation for the L- and D-enantiomers suggest that for closely related systems the greater the extent of this rotational adjustment the greater would be the value of Iss.5. For the actinidin-substrate combinations, model building suggests that even at the ES complex stage of catalysis it is not possible to approach optimized P2-S2 contacts and the three hydrogen-bonding interactions deduced for papain-ligand complexes in the absence of significant movement of protein conformation. Possible binding modes in which some of the interactions deduced for papain are relaxed are discussed. Consideration of postulated binding modes in the various transition states is shown to account for the order of reactivity reflected in values kcat./Km for the four reactions involving papain (Pap) and actinidin (Act) with the L- and D-enantiomeric substrates: Pap-L much greater than Act-L greater than Pap-D much greater than Act-D.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- M Patel
- Department of Biochemistry, Queen Mary & Westfield College, University of London, U.K
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7
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Gallacher G, Jackson CS, Searcey M, Badman GT, Goel R, Topham CM, Mellor GW, Brocklehurst K. A polyclonal antibody preparation with Michaelian catalytic properties. Biochem J 1991; 279 ( Pt 3):871-81. [PMID: 1953683 PMCID: PMC1151527 DOI: 10.1042/bj2790871] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1. 4-Nitrophenyl 4'-(3-aza-2-oxoheptyl)phenyl carbonate (I), an amide conjugate (XI) involving the carboxy group of 4-nitrophenyl 4'-carboxymethylphenyl phosphate and an amino group of keyhole-limpet haemocyanin, and a fluorescein derivative (XVII) were synthesized. 2. The conjugate (XI) was used as an immunogen with which to raise polyclonal antibodies in multigeneration cross-bred sheep; the fluorescent derivative (XVII) was used for the initial assessment of the antisera via binding assays monitored by fluorescence polarization; the carbonate ester (I) was used as a chromogenic substrate for the investigation of catalytic activity. 3. The IgG from the antiserum of sheep no. 270 was isolated by Na2SO4 precipitation and chromatography on Protein G-Sepharose. 4. This preparation of IgG catalysed the hydrolysis of the carbonate ester (I); the catalysis at pH 8.0 and 25 degrees C obeyed Michaelis-Menten kinetics with at least 25 turnovers, Km = 3.34 microM, and lower limits for kcat. of 0.029 s-1 and for kcat./Km of 8.77 x 10(3) M-1.S-1, on the unlikely assumption that the concentration of catalytic antibody is provided by twice the total IgG concentration (two sites per molecule); probable estimates of the fraction of the total IgG that is anti-haptenic IgG and of the fraction of this that is catalytically active suggest that the values of kcat./Km are actually very much larger than these lower limits. 5. The failure of the antibody preparation to catalyse the hydrolysis of the isomeric 2-nitrophenyl carbonate (II), which differs from compound (I) only in the position of the nitro substituent in the leaving group, compels the view that catalytic activity is due to antibody rather than contaminant enzyme; this conclusion is supported by (a) the failure of the following to discriminate effectively between the isomeric substrates (I) and (II): pig liver carboxylesterase, rabbit liver carboxylesterase (collectively EC 3.1.1.1), whole serum from a non-immunized sheep and whole serum from a sheep immunized with a derivative of 3-O-methylnoradrenaline and (b) the lack of catalytic activity in IgG preparations from sheep immunized with sulphoxide or sulphone analogues of immunogen (XI). 6. The various parameters used for the comparison of the kinetic characteristics of hydrolytic catalytic antibodies are discussed. 7. The characteristics of hydrolysis of compound (I) catalysed by the present polyclonal antibody preparation are shown to be substantially better in most respects than those of analogous reactions of two other carbonate esters catalysed by monoclonal antibodies.
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Affiliation(s)
- G Gallacher
- Department of Biochemistry, Queen Mary and Westfield College, University of London, U.K
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8
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Kinetic parameters of the acyl-enzyme mechanism and conditions for quasi-equilibrium and for optimal catalytic characteristics. Biochem J 1990; 270:561-3. [PMID: 2400403 PMCID: PMC1131762 DOI: 10.1042/bj2700561] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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9
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Kowlessur D, Thomas EW, Topham CM, Templeton W, Brocklehurst K. Dependence of the P2-S2 stereochemical selectivity of papain on the nature of the catalytic-site chemistry. Quantification of selectivity in the catalysed hydrolysis of the enantiomeric N-acetylphenylalanylglycine 4-nitroanilides. Biochem J 1990; 266:653-60. [PMID: 2327954 PMCID: PMC1131189 DOI: 10.1042/bj2660653] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
1. N-Acetyl-L-phenylalanylglycine 4-nitroanilide and its D-enantiomer were synthesized and characterized and used as substrates with which to evaluate stereochemical selectivity in papain (EC 3.4.22.2)-catalysed hydrolysis. 2. Kinetic analysis at pH 6.0, I 0.1, 8.3% (v/v) NN-dimethylformamide and 25 degrees C by using initial-rate data with [S] much less than Km and weighted non-linear regression provided values of kcat./Km for the catalysed hydrolysis of both enantiomers as (kcat./Km)L = 2040 +/- 48 M-1.S-1 and (kcat./Km)D = 5.9 +/- 0.07 M-1.S-1. These data, taken together with individual values of kcat. and Km for the hydrolysis of the L-enantiomer (a) estimated in the present work as kcat. = 3.2 +/- 1.2 S-1 and Km = 1.5 +/- 0.6 mM and (b) reported by Lowe & Yuthavong [(1971) Biochem. J. 124, 107-115] for the reaction at pH 6.0 in 10% (v/v) NN-dimethylformamide and 35 degrees C, as kcat. = 1.3 +/- 0.2 S-1 and Km = 0.88 +/- 0.1 mM, suggest that (kcat./Km)L congruent to 2000 M-1.S-1 and thus that (kcat./Km)L/(kcat./Km)D congruent to 330.3. Model building indicates that both enantiomeric 4-nitroanilides can bind to papain such that the phenyl ring of the N-acetylphenylalanyl group makes hydrophobic contacts in the S2 subsite with preservation of mechanistically relevant hydrogen-bonding interactions and that the main difference is in the positioning of the beta-methylene group. 4. The dependence of P2-S2 stereochemical selectivity of papain on the nature of the catalytic-site chemistry for reactions involving derivatives of N-acetylphenylalanine is discussed. The variation in the index of stereochemical selectivity (ratio of the appropriate kinetic or thermodynamic parameter for a given pair of enantiomeric ligands), from 330 for the overall acylation process of the catalytic act, through 40 and 31 for the reaction at electrophilic sulphur in 2-pyridyl disulphides respectively without and with assistance by (His-159)-Im(+)-H, to 5 for the formation of thiohemiacetal adducts by reaction at aldehydic carbon, is interpreted in terms of the extent to which conformational variation of the bound ligand in the catalytic-site region permits the binding mode of the -CH2-Ph group of the D-enantiomer to approach that of the L-enantiomer.
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Affiliation(s)
- D Kowlessur
- Department of Biochemistry, Medical College of St. Bartholomew's Hospital, University of London, U.K
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Brocklehurst K, Willenbrock F, Salih E. Chapter 2 Cysteine proteinases. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/s0167-7306(09)60016-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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11
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Evans BL, Knopp JA, Horton HR. Effect of hydroxynitrobenzylation of tryptophan-177 on reactivity of active site cysteine-25 in papain. Arch Biochem Biophys 1981; 206:362-71. [PMID: 7224644 DOI: 10.1016/0003-9861(81)90103-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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12
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Yuthavong Y, Suttimool W. Rate constants of individual steps in papain-catalysed reactions. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 523:198-206. [PMID: 629988 DOI: 10.1016/0005-2744(78)90022-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Rate constants for acylation of papain (EC 3.4.22.2) by specific substrates and its subsequent deacylation are derived from kinetic analysis of the reactions in the presence of aminoacetonitrile and methanol. Methyl and ethyl hippurate and methyl N-benzyloxycarbonylglycinate have marginally higher values of rate constants for acylation than for deacylation, while the reverse is true for ethyl N-benzoyl-L-arginate. Both acylation and deacylation are rate-determining for these substrates, while only deacylation irate-determining for methyl-N-acetyl-L-phenylalanylglycinate. Deacylation is the only rate-determining step for p-nitrophenyl esters of hippuric acid, N-benzyloxycarbonylglycine and N-acetyl-L-phenylalanylglycine. These results are discussed in relation to those from inactivation of the enzyme by alkylating agent in the presence of substrate.
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Grimard M. N-alpha-benzoyl arginine ethylester hydrolysis by porcine plasmin. A kinetic study of diethyleneglycol influence on this hydrolysis. FEBS Lett 1975; 54:334-8. [PMID: 236932 DOI: 10.1016/0014-5793(75)80934-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Wharton CW, Cornish-Bowden A, Brocklehurst K, Crook EM. Kinetics of the hydrolysis of N-benzoyl-L-serine methyl ester catalysed by bromelain and by papain. Analysis of modifier mechanisms by lattice nomography, computational methods of parameter evaluation for substrate-activated catalyses and consequences of postulated non-productive binding in bromelain- and papain-catalysed hydrolyses. Biochem J 1974; 141:365-381. [PMID: 4455211 PMCID: PMC1168089 DOI: 10.1042/bj1410365] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. N-Benzoyl-l-serine methyl ester was synthesized and evaluated as a substrate for bromelain (EC 3.4.22.4) and for papain (EC 3.4.22.2). 2. For the bromelain-catalysed hydrolysis at pH7.0, plots of [S(0)]/v(i) (initial substrate concn./initial velocity) versus [S(0)] are markedly curved, concave downwards. 3. Analysis by lattice nomography of a modifier kinetic mechanism in which the modifier is substrate reveals that concave-down [S(0)]/v(i) versus [S(0)] plots can arise when the ratio of the rate constants that characterize the breakdown of the binary (ES) and ternary (SES) complexes is either less than or greater than 1. In the latter case, there are severe restrictions on the values that may be taken by the ratio of the dissociation constants of the productive and non-productive binary complexes. 4. Concave-down [S(0)]/v(i) versus [S(0)] plots cannot arise from compulsory substrate activation. 5. Computational methods, based on function minimization, for determination of the apparent parameters that characterize a non-compulsory substrate-activated catalysis are described. 6. In an attempt to interpret the catalysis by bromelain of the hydrolysis of N-benzoyl-l-serine methyl ester in terms of substrate activation, the general substrate-activation model was simplified to one in which only one binary ES complex (that which gives rise directly to products) can form. 7. In terms of this model, the bromelain-catalysed hydrolysis of N-benzoyl-l-serine methyl ester at pH7.0, I=0.1 and 25 degrees C is characterized by K(m) (1) (the dissociation constant of ES)=1.22+/-0.73mm, k (the rate constant for the breakdown of ES to E+products, P)=1.57x10(-2)+/-0.32x10(-2)s(-1), K(a) (2) (the dissociation constant that characterizes the breakdown of SES to ES and S)=0.38+/-0.06m, and k' (the rate constant for the breakdown of SES to E+P+S)=0.45+/-0.04s(-1). 8. These parameters are compared with those in the literature that characterize the bromelain-catalysed hydrolysis of alpha-N-benzoyl-l-arginine ethyl ester and of alpha-N-benzoyl-l-arginine amide; K(m) (1) and k for the serine ester hydrolysis are somewhat similar to K(m) and k(cat.) for the arginine amide hydrolysis and K(as) and k' for the serine ester hydrolysis are somewhat similar to K(m) and k(cat.) for the arginine ester hydrolysis. 9. A previous interpretation of the inter-relationships of the values of k(cat.) and K(m) for the bromelain-catalysed hydrolysis of the arginine ester and amide substrates is discussed critically and an alternative interpretation involving substantial non-productive binding of the arginine amide substrate to bromelain is suggested. 10. The parameters for the bromelain-catalysed hydrolysis of the serine ester substrate are tentatively interpreted in terms of non-productive binding in the binary complex and a decrease of this type of binding by ternary complex-formation. 11. The Michaelis parameters for the papain-catalysed hydrolysis of the serine ester substrate (K(m)=52+/-4mm, k(cat.)=2.80+/-0.1s(-1) at pH7.0, I=0.1, 25.0 degrees C) are similar to those for the papain-catalysed hydrolysis of methyl hippurate. 12. Urea and guanidine hydrochloride at concentrations of 1m have only small effects on the kinetic parameters for the hydrolysis of the serine ester substrate catalysed by bromelain and by papain.
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Mole JE, Horton HR. A kinetic analysis of the enhanced catalytic efficiency of papain modified by 2-hydroxy-5-nitrobenzylation. Biochemistry 1973; 12:5285-9. [PMID: 4760493 DOI: 10.1021/bi00750a010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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18
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19
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Fink AL, Bender ML. Binding sites for substrate leaving groups and added nucleophiles in papain-catalyzed hydrolyses. Biochemistry 1969; 8:5109-18. [PMID: 5365798 DOI: 10.1021/bi00840a065] [Citation(s) in RCA: 52] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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20
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Brocklehurst K. On the mechanism of the alpha-chymotrypsin-catalysed hydrolysis of 4-cis-benzylidene-2-phenyloxazolin-5-one: Evidence for covalent non-productive binding. FEBS Lett 1969; 5:63-67. [PMID: 11947240 DOI: 10.1016/0014-5793(69)80294-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- K Brocklehurst
- Department of Biochemistry and Chemistry, St. Bartholomew's Hospital Medical College, Charterhouse Square, E.C.1, London, England
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