Appendix: Analysis of pH-dependent kinetics in up to four reactive hydronic states.

Supracrystallographic resolution of interactions contributing to enzyme catalysis by use of natural structural variants and reactivity-probe kinetics. Biochem J (1988) 1.35

Identification of signalling and non-signalling binding contributions to enzyme reactivity. Alternative combinations of binding interactions provide for change in transition-state geometry in reactions of papain. Biochem J (1989) 1.04

A polyclonal antibody preparation with Michaelian catalytic properties. Biochem J (1991) 1.03

Clarification of the pH-dependent kinetic behaviour of papain by using reactivity probes and analysis of alkylation and catalysed acylation reactions in terms of multihydronic state models: implications for electrostatics calculations and interpretation of the consequences of site-specific mutations such as Asp-158-Asn and Asp-158-Glu. Biochem J (1993) 0.97

The interplay of electrostatic fields and binding interactions determining catalytic-site reactivity in actinidin. A possible origin of differences in the behaviour of actinidin and papain. Biochem J (1989) 0.92

A re-appraisal of the structural basis of stereochemical recognition in papain. Insensitivity of binding-site-catalytic-site signalling to P2-chirality in a time-dependent inhibition. Biochem J (1990) 0.90

Catalytic-site characteristics of the porcine calpain II 80 kDa/18 kDa heterodimer revealed by selective reaction of its essential thiol group with two-hydronic-state time-dependent inhibitors: evidence for a catalytic site Cys/His interactive system and an ionizing modulatory group. Biochem J (1993) 0.84

Structure of chymopapain M the late-eluted chymopapain deduced by comparative modelling techniques and active-centre characteristics determined by pH-dependent kinetics of catalysis and reactions with time-dependent inhibitors: the Cys-25/His-159 ion-pair is insufficient for catalytic competence in both chymopapain M and papain. Biochem J (1994) 0.83

Preparation of fully active ficin from Ficus glabrata by covalent chromatography and characterization of its active centre by using 2,2'-depyridyl disulphide as a reactivity probe. Biochem J (1976) 2.53

Characterization of the papain active centre by using two-protonic-state electrophiles as reactivity probes. Evidence for nucleophilic reactivity in the un-interrupted cysteine-25-histidine-159 interactive system. Biochem J (1978) 2.21

PH-dependence of the steady-state rate of a two-step enzymic reaction. Biochem J (1976) 2.08

The equilibrium assumption is valid for the kinetic treatment of most time-dependent protein-modification reactions. Biochem J (1979) 1.82

Effects of pH on enzymes. Methods Enzymol (1979) 1.77

The pH-dependence of second-order rate constants of enzyme modification may provide free-reactant pKa values. Biochem J (1977) 1.73

Supracrystallographic resolution of interactions contributing to enzyme catalysis by use of natural structural variants and reactivity-probe kinetics. Biochem J (1988) 1.35

Consequences of molecular recognition in the S1-S2 intersubsite region of papain for catalytic-site chemistry. Change in pH-dependence characteristics and generation of an inverse solvent kinetic isotope effect by introduction of a P1-P2 amide bond into a two-protonic-state reactivity probe. Biochem J (1988) 1.22

pH-activity curves for enzyme-catalysed reactions in which the hydron is a product or reactant. Biochem J (1987) 1.08

Reactions of papain and of low-molecular-weight thiols with some aromatic disulphides. 2,2'-Dipyridyl disulphide as a convenient active-site titrant for papain even in the presence of other thiols. Biochem J (1973) 3.33

A reporter group delivery system with both absolute and selective specificity for thiol groups and an improved fluorescent probe containing the 7-nitrobenzo-2-oxa-1,3-diazole moiety. Biochem J (1975) 3.17

Covalent chromatography. Preparation of fully active papain from dried papaya latex. Biochem J (1973) 2.79

Reactivities of the various protonic states in the reactions of papain and of L-cysteine with 2,2'- and with 4,4'- dipyridyl disulphide: evidence for nucleophilic reactivity in the un-ionized thiol group of the cysteine-25 residue of papain occasioned by its interaction with the histidine-159-asparagine-175 hydrogen-bonded system. Biochem J (1972) 2.65

Preparation of fully active ficin from Ficus glabrata by covalent chromatography and characterization of its active centre by using 2,2'-depyridyl disulphide as a reactivity probe. Biochem J (1976) 2.53

A necessary modification to the preparation of papain from any high-quality latex of Carica papaya and evidence for the structural integrity of the enzyme produced by traditional methods. Biochem J (1979) 2.20

Specific covalent modification of thiols: applications in the study of enzymes and other biomolecules. Int J Biochem (1979) 2.11

PH-dependence of the steady-state rate of a two-step enzymic reaction. Biochem J (1976) 2.08

The equilibrium assumption is valid for the kinetic treatment of most time-dependent protein-modification reactions. Biochem J (1979) 1.82

4-Chloro-7-nitrobenzo-2-oxa-1,3-diazole as a reactivity probe for the investigation of the thiol proteinases. evidence that ficin and bromelain may lack carboxyl groups conformationally equivalent to that of aspartic acid-158 of papain. Biochem J (1976) 1.77

The pH-dependence of second-order rate constants of enzyme modification may provide free-reactant pKa values. Biochem J (1977) 1.73

Two-protonic-state electrophiles as probes of enzyme mechanisms. Methods Enzymol (1982) 1.70

Covalent chromatography by thiol-disulfide interchange. Methods Enzymol (1974) 1.61

Differences in the interaction of the catalytic groups of the active centres of actinidin and papain. Rapid purification of fully active actinidin by covalent chromatography and characterization of its active centre by use of two-protonic-state reactivity probes. Biochem J (1981) 1.60

A spectrophotometric method for the detection of contaminant chymopapains in preparations of papain. Selective modification of one type of thiol group in the chymopapains by a two-protonic-state reagent. Biochem J (1978) 1.52

Kinetics of the reversible reaction of papain with 5,5'-dithiobis-(2-nitrobenzoate) dianion: evidence for nucleophilic reactivity in the un-ionized thiol group of cysteine-25 and for general acid catalysis by histidine-159 of the reaction of the 5-mercapto-2-nitrobenzoate dianion with the papain-5-mercapto-2-nitrobenzoate mixed disulphide. Biochem J (1972) 1.52

The case for assigning a value of approximately 4 to pKa-i of the essential histidine-cysteine interactive systems of papain, bromelain and ficin. FEBS Lett (1975) 1.50

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) 1.47

In defence of the general validity of the Cha method of deriving rate equations. The importance of explicit recognition of the thermodynamic box in enzyme kinetics. Biochem J (1992) 1.45

Evidence that the active centre of chymopapain A is different from the active centres of some other cysteine proteinases and that the Brønsted coefficient (beta nuc.) for the reactions of thiolate anions with 2,2'-dipyridyl disulphide may be decreased by reagent protonation. Biochem J (1980) 1.44

The mutability of stem bromelain: evidence for perturbation by structural transitions of the parameters that characterize the reaction of the essential thiol group of bromelain with 2,2'-dipyridyl disulphide. Biochem J (1972) 1.42

Evidence for a two-state transition in papain that may have no close analogue in ficin. Differences in the disposition of cationic sites and hydrophobic binding areas in the active centres of papain and ficin. Biochem J (1980) 1.39

The activity of the tissue inhibitors of metalloproteinases is regulated by C-terminal domain interactions: a kinetic analysis of the inhibition of gelatinase A. Biochemistry (1993) 1.36

A re-evaluation of the nomenclature of the cysteine proteinases of Carica papaya and a rational basis for their identification. Biochem J (1983) 1.35

Evidence that binding to the s2-subsite of papain may be coupled with catalytically relevant structural change involving the cysteine-25-histidine-159 diad. Kinetics of the reaction of papain with a two-protonic-state reactivity probe containing a hydrophobic side chain. Biochem J (1979) 1.31

Benzofuroxan as a thiol-specific reactivity probe. Kinetics of its reactions with papain, ficin, bromelain and low-molecular-weight thiols. Biochem J (1977) 1.31

Differences in the chemical and catalytic characteristics of two crystallographically 'identical' enzyme catalytic sites. Characterization of actinidin and papain by a combination of pH-dependent substrate catalysis kinetics and reactivity probe studies targeted on the catalytic-site thiol group and its immediate microenvironment. Biochem J (1987) 1.30

A classical enzyme active center motif lacks catalytic competence until modulated electrostatically. Biochemistry (1997) 1.26

Preparation of cathepsins B and H by covalent chromatography and characterization of their catalytic sites by reaction with a thiol-specific two-protonic-state reactivity probe. Kinetic study of cathepsins B and H extending into alkaline media and a rapid spectroscopic titration of cathepsin H at pH 3-4. Biochem J (1985) 1.26

The reaction of papain with Ellman's reagent (5,5'-dithiobis- (2-nitrobenzoate) dianion). Biochem J (1972) 1.25

Characterization of papaya peptidase A as a cysteine proteinase of Carica papaya L. with active-centre properties that differ from those of papain by using 2,2'-dipyridyl disulphide and 4-chloro-7-nitrobenzofurazan as reactivity probes. Use of two-protonic-state electrophiles in the identification of catalytic-site thiol groups. Biochem J (1982) 1.24

Mechanism of the reaction of papain with substrate-derived diazomethyl ketones. Implications for the difference in site specificity of halomethyl ketones for serine proteinases and cysteine proteinases and for stereoelectronic requirements in the papain catalytic mechanism. Biochem J (1978) 1.24

A general framework of cysteine-proteinase mechanism deduced from studies on enzymes with structurally different analogous catalytic-site residues Asp-158 and -161 (papain and actinidin), Gly-196 (cathepsin B) and Asn-165 (cathepsin H). Kinetic studies up to pH 8 of the hydrolysis of N-alpha-benzyloxycarbonyl-L-arginyl-L-arginine 2-naphthylamide catalysed by cathepsin B and of L-arginine 2-naphthylamide catalysed by cathepsin H. Biochem J (1985) 1.23

The preparation and some properties of bromelain covalently attached to O-(carboxymethyl)-cellulose. Eur J Biochem (1968) 1.22

A marked gradation in active-centre properties in the cysteine proteinases revealed by neutral and anionic reactivity probes. Reactivity characteristics of the thiol groups of actinidin, ficin, papain and papaya peptidase A towards 4,4'-dipyridyl disulphide and 5,5'-dithiobis-(2-nitrobenzoate) dianion. Biochem J (1983) 1.21

Reactivities of neutral and cationic forms of 2,2'-dipyridyl disulphide towards thiolate anions. Detection of differences between the active centres of actinidin, papain and ficin by a three-protonic-state reactivity probe. Biochem J (1979) 1.19

Natural structural variation in enzymes as a tool in the study of mechanism exemplified by a comparison of the catalytic-site structure and characteristics of cathepsin B and papain. pH-dependent kinetics of the reactions of cathepsin B from bovine spleen and from rat liver with a thiol-specific two-protonic-state probe (2,2'-dipyridyl disulphide) and with a specific synthetic substrate (N-alpha-benzyloxycarbonyl-L-arginyl-L-arginine 2-naphthylamide). Biochem J (1984) 1.19

Effects of conformational selectivity and of overlapping kinetically influential ionizations on the characteristics of pH-dependent enzyme kinetics. Implications of free-enzyme pKa variability in reactions of papain for its catalytic mechanism. Biochem J (1983) 1.19

Immobilization of urease by thiol-disulphide interchange with concomitant purification. Eur J Biochem (1974) 1.19

A convenient method of preparation of high-activity urease from Canavalia ensiformis by covalent chromatography and an investigation of its thiol groups with 2,2'-dipyridyl disulphide as a thiol titrant and reactivity probe. Biochem J (1976) 1.19

Evaluation of benzofuroxan as a chromophoric oxidizing agent for thiol groups by using its reactions with papain, ficin, bromelain and low-molecular-weight thiols. Biochem J (1977) 1.18

Propapain and its conversion to papain: a new type of zymogen activation mechanism involving intramolecular thiol-disulphide interchange. Nat New Biol (1973) 1.17

Fresh non-fruit latex of Carica papaya contains papain, multiple forms of chymopapain A and papaya proteinase omega. Biochem J (1985) 1.12

The pre-eminence of k(cat) in the manifestation of optimal enzymic activity delineated by using the Briggs-Haldane two-step irreversible kinetic model. Biochem J (1976) 1.12

Investigation of the catalytic site of actinidin by using benzofuroxan as a reactivity probe with selectivity for the thiolate-imidazolium ion-pair systems of cysteine proteinases. Evidence that the reaction of the ion-pair of actinidin (pKI 3.0, pKII 9.6) is modulated by the state of ionization of a group associated with a molecular pKa of 5.5. Biochem J (1983) 1.11

A general kinetic equation for multihydronic state reactions and rapid procedures for parameter evaluation. Biochem Soc Trans (1990) 1.09

Intramolecular inhibition by enzyme of site-specific modification reactions can mask pKa values characteristic of the reaction pathway: do the side chains of aspartic acid-158 and lysine-156 of papain form an ion-pair? [proceedings]. Biochem Soc Trans (1978) 1.09

Structure-function relationships in the cysteine proteinases actinidin, papain and papaya proteinase omega. Three-dimensional structure of papaya proteinase omega deduced by knowledge-based modelling and active-centre characteristics determined by two-hydronic-state reactivity probe kinetics and kinetics of catalysis. Biochem J (1991) 1.08

pH-activity curves for enzyme-catalysed reactions in which the hydron is a product or reactant. Biochem J (1987) 1.08

Reactions of L-ergothioneine and some other aminothiones with2,2'-and 4,4'-dipyridyl disulphides and of L-ergothioneine with iodoacetamide. 2-Mercaptoimidazoles, 2- and 4-thiopyridones, thiourea and thioacetamide as highly reactive neutral sulphur nucleophils. Biochem J (1974) 1.05

The nature of the perturbation of the michaelis constant of the bromelain-catalysed hydrolysis of alpha-N-benzoyl-L-arginine ethyl ester consequent upon attachment of bromelain to O-(carboxymethyl)-cellulose. Eur J Biochem (1968) 1.05

Identification of signalling and non-signalling binding contributions to enzyme reactivity. Alternative combinations of binding interactions provide for change in transition-state geometry in reactions of papain. Biochem J (1989) 1.04

A polyclonal antibody preparation with Michaelian catalytic properties. Biochem J (1991) 1.03

Evolution of enzyme catalytic power. Characteristics of optimal catalysis evaluated for the simplest plausible kinetic model. Biochem J (1977) 1.02

'Chymopapain S' is chymopapain A. Biochem J (1984) 1.02

Biochemical and X-ray crystallographic studies on shikimate kinase: the important structural role of the P-loop lysine. Protein Sci (2001) 1.02

Ionization characteristics of the Cys-25/His-159 interactive system and of the modulatory group of papain: resolution of ambiguity by electronic perturbation of the quasi-2-mercaptopyridine leaving group in a new pyrimidyl disulphide reactivity probe. Biochem J (1993) 1.01

Enzymatically active papain preferentially induces an allergic response in mice. Biochem Biophys Res Commun (1998) 1.01

D-3-hydroxybutyrate dehydrogenase from Rhodopseudomonas spheroides. Kinetic mechanism from steady-state kinetics of the reaction catalysed by the enzyme in solution and covalently attached to diethylaminoethylcellulose. Biochem J (1973) 1.01

Comparative studies on the 5-aminolaevulinic acid dehydratases from Pisum sativum, Escherichia coli and Saccharomyces cerevisiae. Biochem J (1996) 0.99

Differences between the electric fields of the catalytic sites of papain and actinidin detected by using the thiol-located nitrobenzofurazan label as a spectroscopic reporter group. Biochem J (1984) 0.99

Evidence for a close similarity in the catalytic sites of papain and ficin in near-neutral media despite differences in acidic and alkaline media. Kinetics of the reactions of papain and ficin with chloroacetate. Biochem J (1982) 0.98

Clarification of the pH-dependent kinetic behaviour of papain by using reactivity probes and analysis of alkylation and catalysed acylation reactions in terms of multihydronic state models: implications for electrostatics calculations and interpretation of the consequences of site-specific mutations such as Asp-158-Asn and Asp-158-Glu. Biochem J (1993) 0.97

The highly electrophilic character of 4-chloro-7-nitrobenzofurazan and possible consequences for its application as a protein-labelling reagent. Biochem J (1977) 0.97

Characterization of the hydrolytic activity of a polyclonal catalytic antibody preparation by pH-dependence and chemical modification studies: evidence for the involvement of Tyr and Arg side chains as hydrogen-bond donors. Biochem J (1997) 0.97

Ionization characteristics and chemical influences of aspartic acid residue 158 of papain and caricain determined by structure-related kinetic and computational techniques: multiple electrostatic modulators of active-centre chemistry. Biochem J (2000) 0.97

Preparation and characterization of enzymes from spray-dried papaya (Carica papaya) latex [proceedings]. Biochem Soc Trans (1978) 0.95

Evidence that the lack of high catalytic activity of thiolsubtilisin towards specific substrates may be due to an inappropriately located proton-distribution system. Demonstration of highly nucleophilic character of the thiol group of thiolsubtilisin in the catalytically relevant ionization state of the active centre by use of a two-protonic-state reactivity probe. Biochem J (1981) 0.94

Polyclonal-antibody-catalysed hydrolysis of an aryl nitrophenyl carbonate. Biochem Soc Trans (1990) 0.94

Characterization of the electrostatic perturbation of a catalytic site (Cys)-S-/(His)-Im+H ion-pair in one type of serine proteinase architecture by kinetic and computational studies on chemically mutated subtilisin variants. J Mol Biol (1996) 0.93

The interplay of electrostatic fields and binding interactions determining catalytic-site reactivity in actinidin. A possible origin of differences in the behaviour of actinidin and papain. Biochem J (1989) 0.92

Catalytic antibody activity elicited by active immunisation. Evidence for natural variation involving preferential stabilization of the transition state. Eur J Biochem (1993) 0.92

Variation in aspects of cysteine proteinase catalytic mechanism deduced by spectroscopic observation of dithioester intermediates, kinetic analysis and molecular dynamics simulations. Biochem J (2001) 0.91

The interplay of electrostatic and binding interactions determining active centre chemistry and catalytic activity in actinidin and papain. Biochem J (1989) 0.90

A re-appraisal of the structural basis of stereochemical recognition in papain. Insensitivity of binding-site-catalytic-site signalling to P2-chirality in a time-dependent inhibition. Biochem J (1990) 0.90

Chemical evidence for the pH-dependent control of ion-pair geometry in cathepsin B. Benzofuroxan as a reactivity probe sensitive to differences in the mutual disposition of the thiolate and imidazolium components of cysteine proteinase catalytic sites. Biochem J (1986) 0.90

The house dust mite allergen Der p1 catalytically inactivates alpha 1-antitrypsin by specific reactive centre loop cleavage: a mechanism that promotes airway inflammation and asthma. Biochem Biophys Res Commun (1996) 0.89

Evidence for association-activation effects in reactions of papain from studies on its reactivity towards isomeric two-protonic-state reactivity probes. Biochem J (1979) 0.89

A kinetic method for the study of solvent environments of thiol groups in proteins involving the use of a pair of isomeric reactivity probes and a differential solvent effect. Investigation of the active centre of ficin by using 2,2'- and 4,4'- dipyridyl disulphides as reactivity probes. Biochem J (1980) 0.89

Evaluation of hydrogen-bonding and enantiomeric P2-S2 hydrophobic contacts in dynamic aspects of molecular recognition by papain. Biochem J (1992) 0.89

Evidence for independent molecular identity and functional interaction of the haemagglutinin and cysteine proteinase (gingivain) of Porphyromonas gingivalis. J Med Microbiol (1992) 0.87

A general kinetic approach to investigation of active-site availability in macromolecular catalysts. Biochem J (2000) 0.87

Kinetic analysis of the mechanism of interaction of full-length TIMP-2 and gelatinase A: evidence for the existence of a low-affinity intermediate. Biochemistry (1998) 0.86

The kinetic basis of a general method for the investigation of active site content of enzymes and catalytic antibodies: first-order behaviour under single-turnover and cycling conditions. J Theor Biol (2000) 0.86

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) 0.85

A convenient spectrophotometric assay for the determination of L-ergothioneine in blood. Biochem J (1974) 0.85

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) 0.84

Catalytic-site characteristics of the porcine calpain II 80 kDa/18 kDa heterodimer revealed by selective reaction of its essential thiol group with two-hydronic-state time-dependent inhibitors: evidence for a catalytic site Cys/His interactive system and an ionizing modulatory group. Biochem J (1993) 0.84

Polyclonal antibody-catalysed amide hydrolysis. Biochem J (1992) 0.84

Isolation and characterization of gingivain, a cysteine proteinase from Porphyromonas gingivalis strain W83. Biochem Soc Trans (1990) 0.84

Structure of chymopapain M the late-eluted chymopapain deduced by comparative modelling techniques and active-centre characteristics determined by pH-dependent kinetics of catalysis and reactions with time-dependent inhibitors: the Cys-25/His-159 ion-pair is insufficient for catalytic competence in both chymopapain M and papain. Biochem J (1994) 0.83

The synthesis of co-polymers with pendant functional groups arranged in a predetermined geometry as enzyme models [proceedings]. Biochem Soc Trans (1978) 0.82

A thiol-labelling reagent and reactivity probe containing electrophilic mercury and a chromophoric leaving group. Biochem J (1979) 0.82

Are polyclonal catalytic antibodies heterogeneous? Biochem Soc Trans (1997) 0.82

Substituted pyridines as two-protonic-state reactivity probes, reporter-group delivery vehicles and labelling reagents for the study of thiol enzymes [proceedings]. Biochem Soc Trans (1978) 0.81

D-3-hydroxybutyrate dehydrogenase from Rhodopseudomonas spheroides. Kinetics of radioisotope redistribution at chemical equilibrium catalysed by the enzyme in solutions. Biochem J (1973) 0.81

Comparative resonance Raman spectroscopic and kinetic studies of acyl-enzymes involving papain, actinidin and papaya peptidase II. Biochem J (1984) 0.81

Is the dust mite allergen Der p1 a cysteine proteinase? Biochem Soc Trans (1997) 0.81

Ficin: a cysteine proteinase with binding site-catalytic site signalling characteristics intermediate between those of papain and actinidin. Biochem Soc Trans (1993) 0.81

Additional evidence for the cysteine proteinase nature of gingivain the extracellular proteinase of Porphyromonas gingivalis. Biochem Soc Trans (1993) 0.81