N(6)-Carboxy-methyllysine


Synonyms: N(epsilon)-(carboxymethyl)lysine, (2S)-2-amino-6-(carboxymethylamino)hexanoic acid.
Method(s): GC-MS/MS (1).

What is measured on the same platform, click here.
Platform B: MMA, tHcy, tCys, Met, Ser, Gly, Cysta, Sarc, His, Trp, Kyn, (KTR), HK, KA, XA, AA, HAA, NA, PA, Figlu, Orn, Asp, Glu, Lys, Ala, Phe, Ile, Leu, Pro, Val, Asn, Gln, Thr, Tyr, aKG, 3HIB, aHB, bHB, AcAc, CML, CEL, 2AAA

What is N(6)-carboxymethyllysine?

N(ε)-(carboxymethyl)lysine (CML) is one of the major advanced glycation end products (AGEs). These are generated by the Maillard reaction (MR) during thermal treatment of foods or are formed in vivo by nonenzymatic chemical reactions, taking place in tissues or fluid where significant concentration of glucose, fructose, or more reactive dicarbonyls react with proteins. CML is formed by oxidation of fructosyl-lysine (an Amadori product) (the AGE path) and the direct reaction of glyoxal, produced during lipid peroxidation, with the ε-amino group of lysine (the ALE path). CML and other AGEs in tissues and serum/plasma increase with age, and have been assigned a role in the pathogenesis of age-related, chronic diseases, including diabetes, cardiovascular disease, Alzheimer's disease and renal dysfunction (2, 3).

Performance of the assay

Lower limit of detection (LOD): na.
Within-day CV: 5 %; between-day CV: na.

Indication(s)

Assessment of AGEs status.

Specimen, collection and processing

Patient/subject: No special precaution.
Matrix: Serum or EDTA plasma.
Volume: Minimum volume is 50 µL, but 200 µL is optimal and allows reanalysis.
Preparation and stability: Stable.

Transportation; for general instruction on transportation, click here.

Frozen, on dry ice.

Reported values, interpretation

Reported values: 0.05-0.30 µmol/L
Intraclass correlation coefficient (ICC): na.

Literature

1. Midttun, Ø., McCann, A., Aarseth, O., Krokeide, M., Kvalheim, G., Meyer, K., and Ueland, P.M. (2016). Combined measurement of 6 fat-soluble vitamins and 26 water-soluble functional vitamin markers and amino acids in 50 μL of serum or plasma by high-throughput mass spectrometry. Anal Chem 88, 10427-436.
2. Chaudhuri, J., Bains, Y., Guha, S., Kahn, A., Hall, D., Bose, N., Gugliucci, A., and Kapahi, P. (2018). The role of advanced glycation end products in aging and metabolic diseases: Bridging association and causality. Cell Metab 28, 337-352.
3. Brings, S., Fleming, T., Freichel, M., Muckenthaler, M.U., Herzig, S., and Nawroth, P.P. (2017). Dicarbonyls and advanced glycation end-products in the development of diabetic complications and targets for intervention. Int J Mol Sci 18, 984.