-
Protein Science : a Publication of the... Nov 1995The molar absorption coefficient, epsilon, of a protein is usually based on concentrations measured by dry weight, nitrogen, or amino acid analysis. The studies reported...
The molar absorption coefficient, epsilon, of a protein is usually based on concentrations measured by dry weight, nitrogen, or amino acid analysis. The studies reported here suggest that the Edelhoch method is the best method for measuring epsilon for a protein. (This method is described by Gill and von Hippel [1989, Anal Biochem 182:319-326] and is based on data from Edelhoch [1967, Biochemistry 6:1948-1954]). The absorbance of a protein at 280 nm depends on the content of Trp, Tyr, and cystine (disulfide bonds). The average epsilon values for these chromophores in a sample of 18 well-characterized proteins have been estimated, and the epsilon values in water, propanol, 6 M guanidine hydrochloride (GdnHCl), and 8 M urea have been measured. For Trp, the average epsilon values for the proteins are less than the epsilon values measured in any of the solvents. For Tyr, the average epsilon values for the proteins are intermediate between those measured in 6 M GdnHCl and those measured in propanol. Based on a sample of 116 measured epsilon values for 80 proteins, the epsilon at 280 nm of a folded protein in water, epsilon (280), can best be predicted with this equation: epsilon (280) (M-1 cm-1) = (#Trp)(5,500) + (#Tyr)(1,490) + (#cystine)(125) These epsilon (280) values are quite reliable for proteins containing Trp residues, and less reliable for proteins that do not. However, the Edelhoch method is convenient and accurate, and the best approach is to measure rather than predict epsilon.
Topics: 1-Propanol; Chemical Phenomena; Chemistry, Physical; Cystine; Guanidine; Guanidines; Proteins; Solvents; Spectrophotometry, Ultraviolet; Tryptophan; Tyrosine; Urea; Water
PubMed: 8563639
DOI: 10.1002/pro.5560041120 -
Toxins Jun 2018Cystine-stabilized peptides represent a large family of peptides characterized by high structural stability and bactericidal, fungicidal, or insecticidal properties.... (Review)
Review
Cystine-stabilized peptides represent a large family of peptides characterized by high structural stability and bactericidal, fungicidal, or insecticidal properties. Found throughout a wide range of taxa, this broad and functionally important family can be subclassified into distinct groups dependent upon their number and type of cystine bonding patters, tertiary structures, and/or their species of origin. Furthermore, the annotation of proteins related to the cystine-stabilized family are under-represented in the literature due to their difficulty of isolation and identification. As a result, there are several recent attempts to collate them into data resources and build analytic tools for their dynamic prediction. Ultimately, the identification and delivery of new members of this family will lead to their growing inclusion into the repertoire of commercial viable alternatives to antibiotics and environmentally safe insecticides. This review of the literature and current state of cystine-stabilized peptide biology is aimed to better describe peptide subfamilies, identify databases and analytics resources associated with specific cystine-stabilized peptides, and highlight their current commercial success.
Topics: Animals; Computer Simulation; Cystine; Databases, Factual; Peptides
PubMed: 29921767
DOI: 10.3390/toxins10060251 -
Journal of Pharmacological Sciences Jul 2023Cachexia is a common cancer complication and is associated with weight loss and anorexia. In this study, we investigated the ameliorating effects of cystine and theanine...
Cachexia is a common cancer complication and is associated with weight loss and anorexia. In this study, we investigated the ameliorating effects of cystine and theanine on cancer cachexia using a mouse model. In mice carrying the colon cancer cell line C-26, there was a suppression of body weight increase and reduction in both internal fat and lower limb muscles. Repeated cystine and theanine administration significantly prevented weight loss, internal fat loss, lower limb muscle loss, and serum IL-6 increase in the cachexia model. These results suggested that cystine and theanine may be effective in ameliorating cancer cachexia.
Topics: Humans; Cachexia; Cystine; Neoplasms; Weight Loss
PubMed: 37257943
DOI: 10.1016/j.jphs.2023.04.008 -
Amino Acids Aug 2022It is assumed that genetic diseases affecting the metabolism of cysteine and the kidney function lead to two different kinds of pathologies, namely cystinuria and...
It is assumed that genetic diseases affecting the metabolism of cysteine and the kidney function lead to two different kinds of pathologies, namely cystinuria and cystinosis whereby generate L-cystine crystals. Recently, the presence of L-cysteine crystal has been underlined in the case of cystinosis. Interestingly, it can be strikingly seen that cystine ([-S-CH-CH-(NH)-COOH]) consists of two cysteine (CHNOS) molecules connected by a disulfide (S-S) bond. Therefore, the study of cystine and cysteine is important for providing a better understanding of cystinuria and cystinosis. In this paper, we elucidate the discrepancy between L-cystine and L-cysteine by investigating the theoretical and experimental infrared spectra (IR), X-ray diffraction (XRD) as well as Raman spectra aiming to obtain a better characterization of abnormal deposits related to these two genetic pathologies.
Topics: Cysteine; Cystine; Cystinosis; Cystinuria; Disulfides; Humans
PubMed: 35296914
DOI: 10.1007/s00726-022-03144-6 -
Proceedings of the Royal Society of... Oct 1954
Topics: Cystine; Cystinosis
PubMed: 13215530
DOI: No ID Found -
Archives of Disease in Childhood Aug 1952
Topics: Cystine; Cystinosis; Humans
PubMed: 14953468
DOI: 10.1136/adc.27.134.356 -
Antioxidants & Redox Signaling Jul 2023Over the past decade, extensive research has been dedicated to understanding oxidative cell death, specifically the transition from oxytosis to ferroptosis. Oxytosis was... (Review)
Review
Over the past decade, extensive research has been dedicated to understanding oxidative cell death, specifically the transition from oxytosis to ferroptosis. Oxytosis was initially characterized in 1989 as a calcium-dependent form of nerve cell death induced by glutamate. It was associated with intracellular glutathione depletion and the inhibition of cystine uptake through system xc, a cystine-glutamate antiporter. In 2012, the term "ferroptosis" was coined during a compound screening that aimed to selectively induce cell death in -mutated cancer cells. This screening identified erastin and RSL3 as inhibitors of system xc and glutathione peroxidase 4 (GPX4), respectively, triggering oxidative cell death. Subsequently, the term oxytosis gradually fell out of frequent usage, being replaced by ferroptosis. This editorial provides a narrative review of the significant findings, experimental models, and molecular players involved in ferroptosis, shedding light on its intricate mechanisms. Moreover, it discusses the implications of these findings in various pathological conditions, including neurodegenerative disorders, cancer, and ischemia-reperfusion disease. By summarizing the decade-long progress made in this field, the present Forum serves as a valuable resource for researchers aiming to unravel the complex mechanisms underlying oxidative cell death and explore potential therapeutic interventions. 39, 162-165.
Topics: Ferroptosis; Cystine; Cell Death; Oxidation-Reduction; Oxidative Stress; Glutamates
PubMed: 37288743
DOI: 10.1089/ars.2023.0356 -
European Journal of Nutrition Aug 2022Although acute prolonged strenuous exercise has been shown to increase markers of gastrointestinal permeability and damage, little is known regarding the efficacy of... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
Although acute prolonged strenuous exercise has been shown to increase markers of gastrointestinal permeability and damage, little is known regarding the efficacy of nutritional supplement interventions on the attenuation of exercise-induced gastrointestinal syndrome. This study addressed the effects of oral amino acid supplementation on markers of gastrointestinal permeability and damage in response to exercise.
METHODS
Sixteen active men aged 22.7 ± 2.6 years (mean ± standard deviation) completed placebo or cystine and glutamine supplementation trials in random order. Participants received either a placebo or cystine and glutamine supplements, three times a day for 5 days, separated by a 2-week washout period. On day 6, participants took their designated supplements 30 min before running at a speed corresponding to 75% of maximal oxygen uptake for 1 h, followed by a 4-h rest period. Blood samples were collected pre-exercise, immediately post-exercise, 30 min post-exercise, and 1, 2 and 4 h post-exercise on day 6. The plasma lactulose to mannitol ratio (L:M) and plasma intestinal fatty acid-binding protein (I-FABP) were used as markers of gastrointestinal permeability and damage, respectively.
RESULTS
Plasma L:M (linear mixed model, coefficient ± standard error: - 0.011 ± 0.004, P = 0.0090) and changes (i.e., from pre-exercise) in plasma I-FABP (linear mixed model, - 195.3 ± 65.7 coefficient ± standard error (pg/mL), P = 0.0035) were lower in the cystine and glutamine supplementation trial than in the placebo trial.
CONCLUSION
Oral cystine and glutamine supplementation attenuated the markers of gastrointestinal permeability and damage after 1 h of strenuous running in young men.
TRIAL REGISTRATION NUMBER
UMIN000026008.
DATE OF REGISTRATION
13 December 2018.
Topics: Biomarkers; Cystine; Dietary Supplements; Gastrointestinal Tract; Glutamine; Humans; Male; Permeability; Running; Young Adult
PubMed: 35106632
DOI: 10.1007/s00394-022-02806-1 -
Biological Chemistry Nov 2017The cystine knot disulfide pattern has been found to be widespread in nature, since it has been detected in proteins from plants, marine snails, spiders and mammals.... (Review)
Review
The cystine knot disulfide pattern has been found to be widespread in nature, since it has been detected in proteins from plants, marine snails, spiders and mammals. Cystine knot proteins are secreted proteins. Their functions range from defense mechanisms as toxins, e.g. ion channel or enzyme inhibitors, to hormones, blood factors and growth factors. Cystine knot proteins can be divided into two superordinate groups. (i) The cystine knot peptides, also referred to - with other non-cystine knot proteins - as knottins, with linear and cyclic polypeptide chains. (ii) The cystine knot growth factor family, which is in the focus of this article. The disulfide ring structure of the cystine knot peptides is made up by the half-cystines 1-4 and 2-5, and the threading disulfide bond is formed by the half-cystines, 3-6. In the growth factor group, the disulfides of half-cystines 1 and 4 pass the ring structure formed by the half-cystines 2-5 and 3-6. In this review, special emphasis will be devoted to the growth factor cystine knot proteins and their proregions. The latter have shifted into the focus of scientific interest as their important biological roles are just to be unravelled.
Topics: Animals; Cystine; Humans; Intercellular Signaling Peptides and Proteins; Protein Conformation
PubMed: 28771427
DOI: 10.1515/hsz-2017-0163 -
FEBS Letters Jun 2014The goal of this article is to summarize what has been learned about the major forces stabilizing proteins since the late 1980s when site-directed mutagenesis became... (Review)
Review
The goal of this article is to summarize what has been learned about the major forces stabilizing proteins since the late 1980s when site-directed mutagenesis became possible. The following conclusions are derived from experimental studies of hydrophobic and hydrogen bonding variants. (1) Based on studies of 138 hydrophobic interaction variants in 11 proteins, burying a -CH2- group on folding contributes 1.1±0.5 kcal/mol to protein stability. (2) The burial of non-polar side chains contributes to protein stability in two ways: first, a term that depends on the removal of the side chains from water and, more importantly, the enhanced London dispersion forces that result from the tight packing in the protein interior. (3) Based on studies of 151 hydrogen bonding variants in 15 proteins, forming a hydrogen bond on folding contributes 1.1±0.8 kcal/mol to protein stability. (4) The contribution of hydrogen bonds to protein stability is strongly context dependent. (5) Hydrogen bonds by side chains and peptide groups make similar contributions to protein stability. (6) Polar group burial can make a favorable contribution to protein stability even if the polar group is not hydrogen bonded. (7) Hydrophobic interactions and hydrogen bonds both make large contributions to protein stability.
Topics: Cystine; Entropy; Humans; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Protein Conformation; Protein Stability; Proteins
PubMed: 24846139
DOI: 10.1016/j.febslet.2014.05.006