cystine

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cystine

 [sis´tēn, sis´tin]
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.
Synonym(s): dicysteine
Farlex Partner Medical Dictionary © Farlex 2012

cystine

(sĭs′tēn′)
n.
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.

cys·tine

(sis'tēn)
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
Cystineclick for a larger image
Fig. 127 Cystine . Formation of cystine.

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
References in periodicals archive ?
Co-administration of l-cystine and l-theanine enhances efficacy of influenza vaccination in elderly persons: nutritional status-dependent immunogenicity.
Enhancement of antigen-specific immunoglobulin G production in mice by co-administration of l-cystine and l-theanine.
* Taken together for two weeks prior to vaccination, the amino acids L-theanine and L-cystine enhance efficacy of the flu vaccine in a subset of elderly subjects.
The amino acids L-theanine and L-cystine are known for their ability to boost factors of the immune system that are diminished with age: glutathione and interleukin-2.
However, when taken together for two weeks prior to vaccination, the amino acids L-theanine and L-cystine boost the efficacy of the flu vaccine in certain elderly subjects by enhancing the immune system itself.
The study team reported that, together, L-theanine and L-cystine represent an effective and safe natural ingredient to suppress the common cold--producing no more side effects than placebo.
Over a five-week period, the L-theanine and L-cystine group developed 58% fewer colds than the placebo group.
The report concluded that, "Co-administration of L-cystine and L-theanine before vaccination may enhance the immune response to influenza vaccine in elderly subjects with low serum total protein or hemoglobin."