Erratum
for Melnyk et al., Clin Chem 46 (2) 265-272.
Clinical Chemistry 47: 612-a, 2001;
(Clinical Chemistry. 2001;47:612-612 .)
© 2001 American Association for Clinical Chemistry, Inc.
Measurement of Plasma and Intracellular S–Adenosylmethionine and S–Adenosylhomocysteine Utilizing Coulometric Electrochemical Detection: Alterations with Plasma Homocysteine and Pyridoxal 5'–Phosphate. Concentrations
Stepan Melnyk,
Marta Pogribna,
Igor P. Pogribny,
Ping Yi and
S. Jill James
In the article by S. Melnyk, M. Pogribna, I.P. Pogribny, P. Yi,
and S.J. James, entitled "Measurement of Plasma and Intracellular
S-Adenosylmethionine and S-Adenosylhomocysteine
Utilizing Coulometric Electrochemical Detection: Alterations with
Plasma Homocysteine and Pyridoxal 5'-Phosphate Concentrations" (Clin
Chem 2000;46:265–72), the values reported for plasma
S-adenosylmethionine (SAM) were overestimated by a factor of
2.1 because of a calibration error. The corrected mean for plasma SAM
obtained with coulometric electrochemical detection in this article is
73.5 ± 6.7 nmol/L. Please note this correction when referencing this
method. The authors apologize for any inconvenience this error may have
caused. Readers should be aware that the formula weight (FW) provided
by Sigma Chemicals, Inc., for the SAM p-toluenesulfonate
standard may be misleading. The FW provided (399) refers to the
molecular weight of the free base, not the total FW of the SAM
toluenesulfonate salt. The MW for toluenesulfonate (172) is not
provided by Sigma, and it is important to note that the formula
mole/mole ratio (base/salt) can vary from 2 to 4 between individual
lots as does the mole/mole ratio of water. These variables must be
properly corrected for each lot.
