Studies on the amide and C-terminal residues in proteins. 3. The esterification of proteins
- 1 January 1958
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 68 (1) , 114-118
- https://doi.org/10.1042/bj0680114
Abstract
Methods of esterifyingproteins were investigated in detail. It was not possible to esterify a protein fully with daizomethane, even when the reaction was allowed toproceed below pH5. Full esterification can be achieved with methanolic 0.1 [image]HCl in 24 hours, in confirmation of the results of earlier workers. The hydrolytic loss of amide N is, however, much greater than has hitherto been reported. Data are presented to show the relative rates of esterification of aspartyl, asparaginyl and glutamyl residues in insulin and [beta]-lactoglobulin. There is an increase of amino N (Van Slyke) on esterification of proteins with methanolic 0.1[image]HC1. The effect is reversed in an alkaline medium and is due to an N-0 acyl shift in serine and threonine residues.Keywords
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