Cystathionine



Method(s): GC-MS/MS (1), LC-MS/MS (2, 3).

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
Platform C: Chol, (tChol), TMAO, Bet, DMG, tHcy, Creat, Crn, Met, MetSo, Cysta, tCys, His, 3-MH, 1-MH, Arg, ADMA, SDMA, hArg, TML
Platform D: PLP, PL, PA, (PAr), PN, Thi, TMP, Ribo, FMN, Cysta, Neopt, Trp, Kyn, (KTR), KA, AA, HK, XA, (HK/XA), HAA, Pic, QA, NA, NAM, mNAM, Cot, OHCot, Trig

What is cystathionine?

Cystathionine is a thioether and an intermediate metabolite of the transsulfuration pathway where homocysteine is converted to cysteine. Both the enzymes responsible for cystathionine formation (cystathionine beta-synthase) and degradation (cystathionine gamma-lyase) are dependent on vitamin B6 (pyridoxal 5'-phosphate).
Cystathionine increases moderately in conditions associated with elevated tHcy (folate and cobalamin deficiencies), markedly in patients with the inborn error, cystathioninuria/cystathionase deficiency, and decreases moderately after intake of vitamin B6 supplements.

Performance of the assay (GC-MS/MS)

Lower limit of detection (LOD): 0.5 nmol/L.
Within-day CV: 2 %; between-day CV: 6 %.

Indication(s)

Assessment of homocysteine and one-carbon status. Diagnosis of cystathioninuria/cystathionase deficiency. Cystathionine increases during B6-deficiency.

Specimen, collection and processing

Patient/subject: Prandial status affects concentration, which increases up to 3-fold after a protein rich meal.
Matrix: Serum or EDTA plasma.
Volume: Volume: Minimum volume is 50 µL, but 200 µL is optimal and allows reanalysis.
Preparation and stability: Cystathionine is stable.

Transportation; for general instruction on transportation, click here.

Frozen, on dry ice.

Reported values, interpretation

Reported values: 0.07-0.55 µmol/L
Intraclass correlation coefficient (ICC): 0.63.

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. Midttun, O., Kvalheim, G., and Ueland, P.M. (2013). High-throughput, low-volume, multianalyte quantification of plasma metabolites related to one-carbon metabolism using HPLC-MS/MS. Anal Bioanal Chem 405, 2009-017.
3. Midttun, O., Hustad, S., and Ueland, P.M. (2009). Quantitative profiling of biomarkers related to B-vitamin status, tryptophan metabolism and inflammation in human plasma by liquid chromatography/tandem mass spectrometry. Rapid Commun Mass Sp 23, 1371-79.