title: Correction for the suppressive effect of haemoglobin on NADH absorbance in the transketolase assay.
abstract: The kinetic transketolase assay measures the absorbance change of NADH in the presence of haemoglobin. Haemoglobin was shown to suppress NADH absorbance which resulted in an apparently lower enzyme activity. To minimise this suppression, the transketolase assay was performed on samples with haemoglobin concentration of 30 g/l. At this level the absorbance of NADH in the presence of haemoglobin averaged 90.5% of that in Tris buffer. It is proposed that the calculation of the enzyme activity should be corrected for this suppression.
mesh_terms: D005188:False Negative Reactions; D005260:Female; D006452:Hemoglobinometry; D006454:Hemoglobins; D006801:Humans; D008297:Male; D009243:NAD / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014174:Transketolase / Q000032:analysis*
chemical_list: D006454:Hemoglobins; D009243:NAD; D014174:Transketolase