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Literature DB >> 7006597

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.

K Brocklehurst, B S Baines, M S Mushiri.

Abstract

The active centres of chymopapains A and B (jointly designated EC 3.4.22.6) and papaya (Carica papaya L.) peptidase A were investigated by using 2,2'-dipyridyl disulphide and 5,5'-dithiobis-(2-nitrobenzoic acid) as thiol-specific reactivity probes. Whereas the first active-centre pKa values for chymopapain B and papaya peptidase A are less than 5, is as the case for papain (EC 3.4.22.2) and ficin (EC 3.4.22.3), that for chymopapain A is about 6.8. The reason why the reactions of thiols of pKa approx. 6.5 with 2.2'-dipyridyl disulphide are essentially pH-independent in the pH range around the thiol pKa is delineated. The value of the Brønsted coefficient (beta nuc.) for the reactions of thiolate ions with the 2,2'-dipyridyl disulphide monocation appears to be smaller than its value for the corresponding reactions with the neutral disulphide.

Entities: Chemical Species

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Year: 1980 PMID： 7006597 PMCID： PMC1161932 DOI： 10.1042/bj1890189

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

9 in total

1. Isolation and characterization of papaya peptidase A from commercial chymopapain.

Authors: G W Robinson
Journal: Biochemistry Date: 1975-08-12 Impact factor: 3.162

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. 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.

Authors: B S Baines; K Brocklehurst
Journal: Biochem J Date: 1978-07-01 Impact factor: 3.857

4. Chymopapain. IV. The chromatographic fractionation of partially purified chymopapain and the characterization of crystalline chymopapain B.

Authors: D K Kunimitsu; K T Yasunobu
Journal: Biochim Biophys Acta Date: 1967-07-11

5. 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.

Authors: J P Malthouse; K Brocklehurst
Journal: Biochem J Date: 1976-11 Impact factor: 3.857

6. 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

7. 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.

Authors: B S Baines; K Brocklehurst
Journal: Biochem J Date: 1979-02-01 Impact factor: 3.857

8. 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.

Authors: K Brocklehurst; T Stuchbury; J P Malthouse
Journal: Biochem J Date: 1979-11-01 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

9 in total

1. Chymopapain A. Purification and investigation by covalent chromatography and characterization by two-protonic-state reactivity-probe kinetics, steady-state kinetics and resonance Raman spectroscopy of some dithioacyl derivatives.

Authors: B S Baines; K Brocklehurst; P R Carey; M Jarvis; E Salih; A C Storer
Journal: Biochem J Date: 1986-01-01 Impact factor: 3.857

2. Problems of classification of papaya latex proteinases.

Authors: L Polgár
Journal: Biochem J Date: 1984-07-15 Impact factor: 3.857

3. 'Chymopapain S' is chymopapain A.

Authors: K Brocklehurst; B S Baines; E Salih; C Hatzoulis
Journal: Biochem J Date: 1984-07-15 Impact factor: 3.857

4. A re-evaluation of the nomenclature of the cysteine proteinases of Carica papaya and a rational basis for their identification.

Authors: K Brocklehurst; E Salih
Journal: Biochem J Date: 1983-08-01 Impact factor: 3.857

8. 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

9. 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.

Authors: K Brocklehurst; B S Baines; J P Malthouse
Journal: Biochem J Date: 1981-09-01 Impact factor: 3.857

9 in total

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.

1. Isolation and characterization of papaya peptidase A from commercial chymopapain.

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.

3. 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.

4. Chymopapain. IV. The chromatographic fractionation of partially purified chymopapain and the characterization of crystalline chymopapain B.

5. 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.

6. 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.

7. 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.

8. 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.

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.

1. Chymopapain A. Purification and investigation by covalent chromatography and characterization by two-protonic-state reactivity-probe kinetics, steady-state kinetics and resonance Raman spectroscopy of some dithioacyl derivatives.

2. Problems of classification of papaya latex proteinases.

3. 'Chymopapain S' is chymopapain A.

4. A re-evaluation of the nomenclature of the cysteine proteinases of Carica papaya and a rational basis for their identification.

5. Affinity purification of the novel cysteine proteinase papaya proteinase IV, and papain from papaya latex.

6. Chymopapain. Chromatographic purification and immunological characterization.

7. Fresh non-fruit latex of Carica papaya contains papain, multiple forms of chymopapain A and papaya proteinase omega.

9. 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.