title: Disulfide crosslinks and the specificity of protein turnover in plants.
abstract: Studies of the protein metabolism of detached tomato leaves, hormonally induced to accumulate proteinase inhibitors, have indicated that the state of oxidation of protein-bound half-cystine residues may be a principal parameter affecting in vivo and in vitro stability of leaf proteins. Induced leaves exhibited a general specificity of intracellular protein degradation directed towards the preferential hydrolysis of proteins having free-sulfhydryl residues. Proteins having disulfide cross-linkages, including the proteinase inhibitors, were markedly stable to in vivo degradation, and as a result, accumulated. These results provide a precedence for a cellular protein selection process, resulting from a directed specificity of intracellular protein degradation, which is focused on a particular protein structural parameter.
mesh_terms: D003545:Cysteine; D003553:Cystine; D004220:Disulfides; D007700:Kinetics; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D011480:Protease Inhibitors
chemical_list: D004220:Disulfides; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011480:Protease Inhibitors; D003553:Cystine; D003545:Cysteine