Adicionalmente, la dAdo acumulada interfiere con la actividad de la enzima desoxinucleotidil transferasa terminal (TdT), limitando asi la diversidad de los receptores antigeno-especifico de celulas T y se une de forma irreversible a la enzima SAHH
inhibiendo su actividad catalitica (32).
The purpose of this study is to compare the interference of 3-DA on SAHH and rHCYase.
To determine the interference of 3-DA on SAHH, we used S-adenosylhomocysteine (SAH) as a substrate at 50 [micro]mol/L and 3-DA at 0, 50, 100, and 200 [micro]mol/L in the assay buffer.
At 3-DA concentrations ranging from 0 to 200 [micro]mol/L, the relative activity showed almost no change (<4.5%), a striking contrast to the interference of 3-DA on SAHH (Fig.
Here we report the development and testing of two CE methods for the determination of ADA, SAHH, and PNP activity and for the determination of toxic metabolites.
For the determination ADA, PNP, and SAHH activity, we separated Ado, Ino, Hyp, and S-adenosylhomocysteine (SAH) using a Supelco bare CEIect-Fs column [42 cm x 75 [micro]m (i.d.); Supelco Inc.] with the window at a distance of 37.5 cm.
SAHH activity was evaluated as a confirmatory test because it is inhibited by dAdo.
The lower correlation coefficient was 0.9958, obtained for SAHH by plotting sample amounts in microliters of packed RBC vs total activity in pmol/s.
Hcy is estimated by the amount of its metabolic precursor, S-adenosylhomocysteine, formed during the assay by the reverse reaction of the enzyme SAHH. In acid citrate, the low pH may prevent Hcy build up by inhibiting SAHH, but precursor build up is not prevented, thereby giving the impression of sample instability.
We therefore considered a combination of SAHH inhibition by use of 3DA and a slowing of Hcy precursor production by chilling to 2-8[degrees]C.
Chilling samples or storage at ambient temperature in the presence of a SAHH inhibitor (3DA) may both stabilize Hcy to some degree.
As the precursors to Hcy accumulate, SAHH inhibition by 3DA is finally overcome.