A Method for Estimating Glycine in the Presence of Excess Glutamate with o-Phthaldialdehyde

Autor: Lombardo, Maria Elisa, Araujo, Lidia Susana, Branca, Andrea, Batlle, Alcira M. del C.
Zdroj: Zeitschrift für Naturforschung C; August 1990, Vol. 45 Issue: 7-8 p911-914, 4p
Abstrakt: We present a method to determine concentrations of glycine between 1 and 3 mM in the simultaneous presence of 25-100 mM glutamate, which is a modification of the procedure originally described by Klein and Linscr. Z. Physiol. Chem. 205,251 (1932). Glycine and glutamate react with 150 mM w-phthaldialdehyde, glycine is quantitatively con- verted into a colored o-phthaldialdehyde-glycine-glutamate complex. By recording the ab- sorbance of the complex at its maximum peak (around 540 nm). at 600 nm and 480 nm and applying a correction formula is possible to obtain a very good linear correlation when plot- ting the values of corrected absorbance versus the concentration of glycine. From these plots an extinction coefficient of 7.0 x 102cm-1m-1was calculated for the complex. The method is highly reproducible and sensitive and solved the problem of glutamate interference when esti- mating low concentrations of glycine in mixture containing 10 to 50 times concentrations of the former aminoacid.
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