Matches in SemOpenAlex for { <https://semopenalex.org/work/W1887614213> ?p ?o ?g. }
- W1887614213 endingPage "80" @default.
- W1887614213 startingPage "67" @default.
- W1887614213 abstract "1. The u.v.-spectral characteristics of 5,5'-dithiobis-(2-nitrobenzoic acid) (Nbs(2)), 2,2'-dipyridyl disulphide (2-Py-S-S-2-Py), 4,4'-dipyridyl disulphide (4-Py-S-S-4-Py), 5-mercapto-2-nitrobenzoic acid (Nbs), 2-thiopyridone (Py-2-SH) and 4-thiopyridone (Py-4-SH) were determined over a wide range of pH and used to calculate their acid dissociation constants. 2. The reactions of l-cysteine, 2-mercaptoethanol and papain with the above-mentioned disulphides were investigated spectrophotometrically in the pH range 2.5-8.5. 3. Under the conditions of concentration used in this study the reactions of both low-molecular-weight thiols with all three disulphides resulted in the stoicheiometric release of the thiol or thione fragments Nbs, Py-2-SH and Py-4-SH at all pH values. The rates of these reactions are considerably faster at pH8 than at pH4, which suggests that the predominant reaction pathway in approximately neutral media is nucleophilic attack of the thiolate ion on the unprotonated disulphide. 4. The reaction of papain with Nbs(2) is markedly reversible in the acid region, and the pH-dependence of the equilibrium constant for this system in the pH range 5-8 at 25 degrees C and I=0.1 is described by: [Formula: see text] 5. Papain reacts with both 2-Py-S-S-2-Py and 4-Py-S-S-4-Py in the pH range 2.5-8.5 to provide release of the thione fragments, stoicheiometric with the thiol content of the enzyme. 6. Whereas the ratios of the second-order rate constant for the reaction at pH4 to that at pH8 for the cysteine-2-Py-S-S-2-Py reaction (k(pH4)/k(pH8)=0.015) and for the papain-4-Py-S-S-4-Py reaction (k(pH4)/k(pH8)=0.06) are less than 1, that for the papain-2-Py-S-S-2-Py reaction is greater than 1 (k(pH4)/k(pH8)=15). 7. This high reactivity of papain has been shown to involve reaction of the thiol group of cysteine-25, the enzyme's only cysteine residue, which is part of its catalytic site. 8. That this rapid and stoicheiometric reaction of the thiol group of native papain is not shown either by low-molecular-weight thiols or by the thiol group of papain after its active conformation has been destroyed by acid or heat denaturation, strongly commends 2-Py-S-S-2-Py as one of the most useful papain active-site titrants discovered to date. This reagent has been shown to allow accurate titration of papain active sites in the presence of up to 10-fold molar excess of l-cysteine and up to 100-fold molar excess of 2-mercaptoethanol." @default.
- W1887614213 created "2016-06-24" @default.
- W1887614213 creator A5010315998 @default.
- W1887614213 creator A5056593445 @default.
- W1887614213 date "1973-05-01" @default.
- W1887614213 modified "2023-10-14" @default.
- W1887614213 title "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" @default.
- W1887614213 cites W1480971655 @default.
- W1887614213 cites W1541196438 @default.
- W1887614213 cites W1554977141 @default.
- W1887614213 cites W1760014329 @default.
- W1887614213 cites W1821829208 @default.
- W1887614213 cites W1914630957 @default.
- W1887614213 cites W1967383104 @default.
- W1887614213 cites W1973181401 @default.
- W1887614213 cites W1973228970 @default.
- W1887614213 cites W2006370393 @default.
- W1887614213 cites W2007276475 @default.
- W1887614213 cites W2017001003 @default.
- W1887614213 cites W2029389201 @default.
- W1887614213 cites W2031751691 @default.
- W1887614213 cites W2036474910 @default.
- W1887614213 cites W2040524941 @default.
- W1887614213 cites W2067973888 @default.
- W1887614213 cites W2092331199 @default.
- W1887614213 cites W2094184534 @default.
- W1887614213 cites W2097100275 @default.
- W1887614213 cites W2118251635 @default.
- W1887614213 cites W2151939183 @default.
- W1887614213 cites W2160186497 @default.
- W1887614213 cites W2229311549 @default.
- W1887614213 cites W223123442 @default.
- W1887614213 cites W2410105619 @default.
- W1887614213 cites W93161100 @default.
- W1887614213 cites W984100136 @default.
- W1887614213 doi "https://doi.org/10.1042/bj1330067" @default.
- W1887614213 hasPubMedCentralId "https://www.ncbi.nlm.nih.gov/pmc/articles/1177671" @default.
- W1887614213 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/4721623" @default.
- W1887614213 hasPublicationYear "1973" @default.
- W1887614213 type Work @default.
- W1887614213 sameAs 1887614213 @default.
- W1887614213 citedByCount "159" @default.
- W1887614213 countsByYear W18876142132012 @default.
- W1887614213 countsByYear W18876142132014 @default.
- W1887614213 countsByYear W18876142132015 @default.
- W1887614213 countsByYear W18876142132016 @default.
- W1887614213 countsByYear W18876142132017 @default.
- W1887614213 countsByYear W18876142132018 @default.
- W1887614213 countsByYear W18876142132019 @default.
- W1887614213 countsByYear W18876142132020 @default.
- W1887614213 crossrefType "journal-article" @default.
- W1887614213 hasAuthorship W1887614213A5010315998 @default.
- W1887614213 hasAuthorship W1887614213A5056593445 @default.
- W1887614213 hasBestOaLocation W18876142132 @default.
- W1887614213 hasConcept C102931765 @default.
- W1887614213 hasConcept C121332964 @default.
- W1887614213 hasConcept C148898269 @default.
- W1887614213 hasConcept C155647269 @default.
- W1887614213 hasConcept C161790260 @default.
- W1887614213 hasConcept C170493617 @default.
- W1887614213 hasConcept C178790620 @default.
- W1887614213 hasConcept C178907741 @default.
- W1887614213 hasConcept C179104552 @default.
- W1887614213 hasConcept C181199279 @default.
- W1887614213 hasConcept C184651966 @default.
- W1887614213 hasConcept C184866935 @default.
- W1887614213 hasConcept C185592680 @default.
- W1887614213 hasConcept C22163223 @default.
- W1887614213 hasConcept C2779201268 @default.
- W1887614213 hasConcept C2779832904 @default.
- W1887614213 hasConcept C2781324293 @default.
- W1887614213 hasConcept C55493867 @default.
- W1887614213 hasConcept C62520636 @default.
- W1887614213 hasConcept C71240020 @default.
- W1887614213 hasConcept C74998103 @default.
- W1887614213 hasConcept C93391505 @default.
- W1887614213 hasConceptScore W1887614213C102931765 @default.
- W1887614213 hasConceptScore W1887614213C121332964 @default.
- W1887614213 hasConceptScore W1887614213C148898269 @default.
- W1887614213 hasConceptScore W1887614213C155647269 @default.
- W1887614213 hasConceptScore W1887614213C161790260 @default.
- W1887614213 hasConceptScore W1887614213C170493617 @default.
- W1887614213 hasConceptScore W1887614213C178790620 @default.
- W1887614213 hasConceptScore W1887614213C178907741 @default.
- W1887614213 hasConceptScore W1887614213C179104552 @default.
- W1887614213 hasConceptScore W1887614213C181199279 @default.
- W1887614213 hasConceptScore W1887614213C184651966 @default.
- W1887614213 hasConceptScore W1887614213C184866935 @default.
- W1887614213 hasConceptScore W1887614213C185592680 @default.
- W1887614213 hasConceptScore W1887614213C22163223 @default.
- W1887614213 hasConceptScore W1887614213C2779201268 @default.
- W1887614213 hasConceptScore W1887614213C2779832904 @default.
- W1887614213 hasConceptScore W1887614213C2781324293 @default.
- W1887614213 hasConceptScore W1887614213C55493867 @default.
- W1887614213 hasConceptScore W1887614213C62520636 @default.
- W1887614213 hasConceptScore W1887614213C71240020 @default.
- W1887614213 hasConceptScore W1887614213C74998103 @default.
- W1887614213 hasConceptScore W1887614213C93391505 @default.