Biomaterial Database

Oxidation of cysteine residues from alpha-A crystallin during cataractogenesis of the human lens. 1996

L J Takemoto

Division of Biology, Kansas State University, Manhattan 66506, USA.

Although it has been known for many years that opacification of the human lens is accompanied by oxidation of cysteine sulfhydryl groups to half-cystine residues, nothing is known concerning the exact amino acid sequences involved in this oxidative process. Since alpha-A crystallin is one of the major proteins of the lens, and since a decrease in its molecular chaperone activity has been implicated in possible mechanisms of cataract formation, alpha-A crystallin was purified from total lens proteins by reverse phase chromatography, followed by digestion with lys-C endoprotease. Mass spectral analysis of the digest indicated that in normal transparent lenses, cys-131 and cys-142 from alph-A crystallin are present as a mixture of cysteine sulfhydryl and half-cysteine disulfide groups, while identical analysis from cataractous lenses demonstrated undetectable levels of the cysteine sulfhydryl group. Together, these results demonstrate for the first time, the involvement of specific cysteine residues in the oxidative mechanism of human lens opacification.

UI	MeSH Term	Description	Entries
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D002386	Cataract	Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)	Cataract, Membranous,Lens Opacities,Pseudoaphakia,Cataracts,Cataracts, Membranous,Lens Opacity,Membranous Cataract,Membranous Cataracts,Opacities, Lens,Opacity, Lens,Pseudoaphakias
D003459	Crystallins	A heterogeneous family of water-soluble structural proteins found in cells of the vertebrate lens. The presence of these proteins accounts for the transparency of the lens. The family is composed of four major groups, alpha, beta, gamma, and delta, and several minor groups, which are classed on the basis of size, charge, immunological properties, and vertebrate source. Alpha, beta, and delta crystallins occur in avian and reptilian lenses, while alpha, beta, and gamma crystallins occur in all other lenses.	Lens Proteins,Crystallin,Eye Lens Protein,Lens Protein, Eye,Protein, Eye Lens,Proteins, Lens
D003545	Cysteine	A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.	Cysteine Hydrochloride,Half-Cystine,L-Cysteine,Zinc Cysteinate,Half Cystine,L Cysteine
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000693	Anaerobiosis	The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Anaerobic Metabolism,Anaerobic Metabolisms,Anaerobioses,Metabolism, Anaerobic,Metabolisms, Anaerobic
D013058	Mass Spectrometry	An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.	Mass Spectroscopy,Spectrometry, Mass,Spectroscopy, Mass,Spectrum Analysis, Mass,Analysis, Mass Spectrum,Mass Spectrum Analysis,Analyses, Mass Spectrum,Mass Spectrum Analyses,Spectrum Analyses, Mass
D018833	Chaperonins	A family of multisubunit protein complexes that form into large cylindrical structures which bind to and encapsulate non-native proteins. Chaperonins utilize the energy of ATP hydrolysis to enhance the efficiency of PROTEIN FOLDING reactions and thereby help proteins reach their functional conformation. The family of chaperonins is split into GROUP I CHAPERONINS, and GROUP II CHAPERONINS, with each group having its own repertoire of protein subunits and subcellular preferences.	Chaperonin,Chaperonin Complex,Chaperonin Complexes,Chaperonin Family,Chaperonin Protein Complex,Complex, Chaperonin