Literature DB >> 534503

Evidence for association-activation effects in reactions of papain from studies on its reactivity towards isomeric two-protonic-state reactivity probes.

K Brocklehurst, J A Herbert, R Norris, H Suschitzky.   

Abstract

4-(N-Aminoethyl 4-pyridyl disulphide)-7-nitrobenzo-2-oxa-1,3-diazole was synthesized and evaluted as a two-protonic-state reactivity probe by kinetic study of its reactions with papain (EC 3.4.22.2) and with benzimidazol-2-ylmethanethiol. Evidence is presented to suggest that: (i) both this probe molecule and its 2-pyridyl isomer bind to papain; (ii) the binding is followed by a change in the environment of the thiol group of cysteine-25; (iii) the striking rate maximum in neutral media observed in the reaction of papain with the 2-pyridyl isomer but not with the 4-pyridyl isomer arises from association of the 2-pyridyl leaving group with the imidazolium ion of histidine-159.

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Year:  1979        PMID： 534503      PMCID： PMC1161567          DOI： 10.1042/bj1830369

Source DB:  PubMed          Journal:  Biochem J        ISSN： 0264-6021            Impact factor:   3.857


  11 in total

1.  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.

Authors:  T Stuchbury; M Shipton; R Norris; J P Malthouse; K Brocklehurst; J A Herbert; H Suschitzky
Journal:  Biochem J       Date:  1975-11       Impact factor: 3.857

2.  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.

Authors:  M Shipton; K Brochlehurst
Journal:  Biochem J       Date:  1978-05-01       Impact factor: 3.857

3.  Specific covalent modification of thiols: applications in the study of enzymes and other biomolecules.

Authors:  K Brocklehurst
Journal:  Int J Biochem       Date:  1979

4.  Mapping the active site of papain with the aid of peptide substrates and inhibitors.

Authors:  A Berger; I Schechter
Journal:  Philos Trans R Soc Lond B Biol Sci       Date:  1970-02-12       Impact factor: 6.237

5.  The equilibrium assumption is valid for the kinetic treatment of most time-dependent protein-modification reactions.

Authors:  K Brocklehurst
Journal:  Biochem J       Date:  1979-09-01       Impact factor: 3.857

6.  Cryoenzymology of papain: reaction mechanism with an ester substrate.

Authors:  K J Angelides; A L Fink
Journal:  Biochemistry       Date:  1978-06-27       Impact factor: 3.162

7.  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.

Authors:  K Brocklehurst; J P Malthouse
Journal:  Biochem J       Date:  1978-11-01       Impact factor: 3.857

8.  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.

Authors:  K Brocklehurst; G Little
Journal:  Biochem J       Date:  1973-05       Impact factor: 3.857

9.  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.

Authors:  K Brocklehurst; J P Malthouse; M Shipton
Journal:  Biochem J       Date:  1979-11-01       Impact factor: 3.857

10.  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.

Authors:  K Brocklehurst; G Little
Journal:  Biochem J       Date:  1972-06       Impact factor: 3.857
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  5 in total

1.  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.

Authors:  K Brocklehurst; S J Willenbrock; E Salih
Journal:  Biochem J       Date:  1983-06-01       Impact factor: 3.857

2.  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.

Authors:  K Brocklehurst; J P Malthouse
Journal:  Biochem J       Date:  1980-12-01       Impact factor: 3.857

3.  Kinetic solvent isotope effects on the deacylation of specific acyl-papains. Proton inventory studies on the papain-catalysed hydrolyses of specific ester substrates: analysis of possible transition state structures.

Authors:  R J Szawelski; C W Wharton
Journal:  Biochem J       Date:  1981-12-01       Impact factor: 3.857

4.  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.

Authors:  K Brocklehurst; J P Malthouse
Journal:  Biochem J       Date:  1981-03-01       Impact factor: 3.857

5.  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.

Authors:  K Brocklehurst; D Kowlessur; G Patel; W Templeton; K Quigley; E W Thomas; C W Wharton; F Willenbrock; R J Szawelski
Journal:  Biochem J       Date:  1988-03-15       Impact factor: 3.857
  5 in total

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