cystine(redirected from E921)
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a naturally occurring amino acid, the chief sulfur-containing component of the protein molecule. It is sometimes found in the urine and in the kidneys in the form of minute hexagonal crystals, frequently forming cystine calculus in the bladder.
cystine storage disease Fanconi's syndrome (def. 2).
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
cys·tine(sis'tēn, sis'tin), Do not confuse this word with cysteine.
3,3'-Dithiobis(2-aminopropionic acid); the disulfide product of two cysteines in which two -SH groups become one -S-S- group; if two cysteinyl residues in polypeptide chains form a disulfide linkage, then the two polymers are cross-linked; sometimes occurs as a deposit in the urine, or forming a vesical calculus. Compare: meso-cystine.
Farlex Partner Medical Dictionary © Farlex 2012
A white crystalline amino acid, C6H12N2O4S2, that is formed from the disulfide linkage of two cysteines during the folding of many proteins, especially keratin, and stabilizes the tertiary structure of the protein.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
The disulfide product of two cysteines in which two -SH groups become one -S-S- group; sometimes occurs as a deposit in the urine, or forming a vesical calculus.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
cystine [Cys-Cys]an amino acid residue formed by the OXIDATION of the sulphydryl groups [SH] of two CYSTEINES generating a DISULPHIDE BRIDGE (S-S); See Fig. 127 . In some PROTEINS, side chains can be cross-linked by disulphide bridges as a result of the formation of cystines. See SULPHUR BRIDGE.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005