{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,20]],"date-time":"2026-09-20T21:02:01Z","timestamp":1789938121802,"version":"4.0.1"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"3","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1980,9,1]]},"abstract":"<jats:p>The degradation of S\u2013S bonds in 0.2 M-NaOH at 25 degrees C was studied for a series of proteins and simple aliphatic disulphide compounds, by using cathodic stripping voltammetry, ion-selective-electrode potentiometry, spectrophotometry and ultrafiltration. The disulphide bonds that dissociated in 0.2 M-NaOH were usually those that are solvent accessible and that can be reduced by mild chemical reductants. Some unexpected differences were found between similar proteins, both in the number of S\u2013S bonds dissociated and in their rates of decomposition. Chymotrypsin has one S\u2013S bond attacked, whereas chymotrypsinogen and trypsinogen have two. Ribonuclease A has two S\u2013S bonds dissociated, but ribonuclease S and S-protein have three. Denaturation in 6 M-guanidine hydrochloride before alkaline digestion caused the loss of an additional S\u2013S bond in ribonuclease A and insulin, and increased the rate of dissociation of the S\u2013S bonds of some other proteins. The initial product of S\u2013S bond dissociation in dilute alkali is believed to be a persulphide intermediate formed by a beta-elimination reaction. This intermediate is in mobile equilibrium with bisulphide ion, HS-, and decomposes at a mercury electrode or in acid solution to yield a stoichiometric amount of sulphide. Rate constants and equilibrium constants were measured for the equilibria between HS- and the intermediates involved in the alkaline dissociation of several proteins. Elemental sulphur was not detected in any of the protein digests. It is suggested that formation of HS- from a persulphide intermediate involves a hydrolysis reaction to yield a sulphenic acid derivative. The small polypeptides glutathione and oxytocin gave only a low yield of persulphide, and their alkaline decomposition must proceed by a mechanism different from that of the proteins.<\/jats:p>","DOI":"10.1042\/bj1890507","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T20:22:52Z","timestamp":1439238172000},"page":"507-520","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":147,"title":["Degradation of protein disulphide bonds in dilute alkali"],"prefix":"10.1042","volume":"189","author":[{"given":"T M","family":"Florence","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/189\/3\/507\/574430\/bj1890507.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/189\/3\/507\/574430\/bj1890507.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,25]],"date-time":"2021-11-25T12:22:14Z","timestamp":1637842934000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/189\/3\/507\/11912\/Degradation-of-protein-disulphide-bonds-in-dilute"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1980,9,1]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1980,9,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj1890507","relation":{},"ISSN":["0264-6021"],"issn-type":[{"value":"0264-6021","type":"print"}],"subject":[],"published":{"date-parts":[[1980,9,1]]}}}