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MAK255

Sigma-Aldrich

Cysteine Assay Kit (Fluorometric)

sufficient for 100 fluorometric tests

Synonym(s):

Cysteine Quantitation Kit

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About This Item

UNSPSC Code:
12161503
NACRES:
NA.84
Pricing and availability is not currently available.

detection method

fluorometric

relevant disease(s)

cardiovascular diseases

storage temp.

−20°C

General description

Cysteine (CYS) is a non-essential, sulfur containing amino acid in humans, related to cystine. Cysteine is important for protein synthesis, detoxification, and diverse metabolic functions. It is found in beta-keratin, which comprises the main protein in nails, skin, and hair. Cysteine is also important in collagen production, as well as skin elasticity and texture. A component of the antioxidant, glutathione, cysteine plays a role in the metabolism of essential biochemicals such as coenzyme A, heparin, and biotin. An elevated level of total cysteine can predict cardiovascular disease and metabolic syndromes. Cysteine deficiency is known to be one of the consequences of aging.[1]

Features and Benefits

Compatible with high-throughput handling systems.

Suitability

Suitable for the detection of cysteine in serum, plasma, and other biological fluids.

Principle

The Cysteine Assay Kit detects the physiological concentration of cysteine in a variety of biological fluids. The assay is based on the cleavage of thiol group of reduced cysteine generating a fluorometric product (ex = 365 nm/ em = 450 nm), directly proportional to the amount of total cysteine in the sample. The assay is specific and other thiol-based amino acids do not interfere with the assay. This high-throughput adaptable assay kit is simple and sensitive enough to detect to 10 µM of cysteine in a variety of samples.

Storage Class Code

10 - Combustible liquids

Flash Point(F)

188.6 °F - closed cup

Flash Point(C)

87 °C - closed cup


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Kazuki Hayashima et al.
The Journal of biological chemistry, 298(3), 101703-101703 (2022-02-13)
Ferroptosis is an iron-dependent mode of cell death caused by excessive oxidative damage to lipids. Lipid peroxidation is normally suppressed by glutathione peroxidase 4, which requires reduced glutathione. Cystine is a major resource for glutathione synthesis, especially in cancer cells.
Oxidative stress and ageing: is ageing a cysteine deficiency syndrome?
Droge W.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 360(1464), 2355-2372 (2005)
Virender Kumar Pal et al.
eLife, 10 (2021-11-19)
A fundamental challenge in human immunodeficiency virus (HIV) eradication is to understand how the virus establishes latency, maintains stable cellular reservoirs, and promotes rebound upon interruption of antiretroviral therapy (ART). Here, we discovered an unexpected role of the ubiquitous gasotransmitter
Xinbo Wang et al.
Cancer research, 81(20), 5217-5229 (2021-08-14)
Ferroptosis is a lipid peroxidation-dependent cell death caused by metabolic dysfunction. Ferroptosis-associated enzymes are promising therapeutic targets for cancer treatment. However, such therapeutic strategies show limited efficacy due to drug resistance and other largely unknown underlying mechanisms. Here we report

Questions

1–4 of 4 Questions  
  1. is this product suitable for cell lysate? If possible, i need protocol to prepare sample(cell number, how to lysis etc.)

    1 answer
    1. This product has been discontinued without a replacement. Technical Service has no data describing its use in testing cell lysates.

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  2. Are the standards run in kinetic or endpoint mode? How are they plotted?

    1 answer
    1. The standards are run in kinetic mode as well. It's important that the delta T (T2-T1) remains consistent for both the standards and the samples, and in all cases, it should fall within the linear range of the plot. For instance, samples could be read from T=2 to T=4 (assuming linearity) and the standards could be read from T=3 to T=5 (again, assuming linearity), ensuring that the delta T remains the same. Subsequently, the delta RFU is plotted for the standards against concentration, and then the samples can be plotted using their delta RFU to determine the concentration.

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  3. Could N-acetyl Cysteine interfere with the MAK255-1KT Cysteine Assay Kit (Fluorometric)? Additionally, would residual H2S also interfere with the assay?

    1 answer
    1. Since the assay principle is based on the cleavage of the thiol group in reduced Cysteine, N-acetyl Cysteine, which contains the thiol group, is likely to be included in the quantification of cysteine present in the biological fluids by the kit. Additionally, the assay should detect Hydrogen sulfide generated by the enzymatic metabolism of Cysteine. Therefore, sulfide salts (such as Sodium sulfide) as well as residual Hydrogen sulfide in the sample would likely be a significant source of interference.

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  4. Is the product Cysteine Assay Kit (Fluorometric) MAK255 suitable for use with blood plasma?

    1 answer
    1. The Cysteine Assay Kit (Fluorometric) MAK255 is suitable for use with mammalian plasma samples. Centrifugation of plasma samples is not necessary, as they can be used directly. While the choice of anticoagulant would not make a significant difference, it is generally recommended to avoid EDTA or citrate, which are chelators, and to use heparin instead.

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