Perils of partitioning: A case study of flavins and flavokinase.
Partitioning is a common procedure for the separation of two solutes from a solution based on their differential solubility in an immiscible solvent. This has been widely used to quantitate riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide in aqueous samples by extraction with water-saturated benzyl alcohol. Here we report that the partitioning of riboflavin and FMN is affected by the presence of each other in a concentration-dependent manner, thus rendering this procedure unsuitable for quantitation. Direct quantitation of FMN formed in assays for flavokinase from Vigna radiata shows that kinetic analyses using a partition-based assay lead to erroneous conclusions.
Das-Panja
K
K
University College of Science, Osmania University, Hyderabad, 500007, India.
Jonnalagadda
V S
VS
Jonnalagadda
S
S
D000255:Adenosine Triphosphate; D002851:Chromatography, High Pressure Liquid; D007887:Fabaceae / Q000201:enzymology; D005486:Flavin Mononucleotide / Q000032:analysis*; D007700:Kinetics; D008274:Magnesium; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000032:analysis*; D010946:Plants, Medicinal; D012256:Riboflavin / Q000032:analysis*; D012996:Solutions
D012996:Solutions; D005486:Flavin Mononucleotide; D000255:Adenosine Triphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C022532:riboflavin kinase; D008274:Magnesium; D012256:Riboflavin