title: Degradative covalent reactions important to protein stability.
abstract: Commonly observed chemical modifications that occur in proteins during their in vitro purification, storage, and handling are discussed. Covalent modifications described include deamidation and isoaspartate formation, cleavage of peptide bonds at aspartic acid residues, cystine destruction and thiol-disulfide interchange, oxidation of cysteine and methionine residues, and the glycation and carbamylation of amino groups.
authors.affiliation: Merck Research Laboratories, West Point, PA 19486, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Volkin
authors.forename: H
authors.initials: H
authors.lastname: Mach
authors.forename: C R
authors.initials: CR
authors.lastname: Middaugh
mesh_terms: D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D003553:Cystine / Q000737:chemistry / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D008715:Methionine / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism
chemical_list: D004220:Disulfides; D011506:Proteins; D013438:Sulfhydryl Compounds; D001224:Aspartic Acid; D003553:Cystine; D008715:Methionine; D003545:Cysteine