Publications

• Dihydroxyacetone metabolism by human erythrocytes: demonstration of triokinase activity and its characterization.

  Beutler E., Guinto E.

  Blood 41:559-568(1973) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Bifunctional homodimeric triokinase/FMN cyclase: contribution of protein domains to the activities of the human enzyme and molecular dynamics simulation of domain movements.

  Rodrigues J.R., Couto A., Cabezas A., Pinto R.M., Ribeiro J.M., Canales J., Costas M.J., Cameselle J.C.

  Mammalian triokinase, which phosphorylates exogenous dihydroxyacetone and fructose-derived glyceraldehyde, is neither molecularly identified nor firmly associated to an encoding gene. Human FMN cyclase, which splits FAD and other ribonucleoside diphosphate-X compounds to ribonucleoside monophospha ... >> More

  Mammalian triokinase, which phosphorylates exogenous dihydroxyacetone and fructose-derived glyceraldehyde, is neither molecularly identified nor firmly associated to an encoding gene. Human FMN cyclase, which splits FAD and other ribonucleoside diphosphate-X compounds to ribonucleoside monophosphate and cyclic X-phosphodiester, is identical to a DAK-encoded dihydroxyacetone kinase. This bifunctional protein was identified as triokinase. It was modeled as a homodimer of two-domain (K and L) subunits. Active centers lie between K1 and L2 or K2 and L1: dihydroxyacetone binds K and ATP binds L in different subunits too distant (≈ 14 Å) for phosphoryl transfer. FAD docked to the ATP site with ribityl 4'-OH in a possible near-attack conformation for cyclase activity. Reciprocal inhibition between kinase and cyclase reactants confirmed substrate site locations. The differential roles of protein domains were supported by their individual expression: K was inactive, and L displayed cyclase but not kinase activity. The importance of domain mobility for the kinase activity of dimeric triokinase was highlighted by molecular dynamics simulations: ATP approached dihydroxyacetone at distances below 5 Å in near-attack conformation. Based upon structure, docking, and molecular dynamics simulations, relevant residues were mutated to alanine, and kcat and Km were assayed whenever kinase and/or cyclase activity was conserved. The results supported the roles of Thr(112) (hydrogen bonding of ATP adenine to K in the closed active center), His(221) (covalent anchoring of dihydroxyacetone to K), Asp(401) and Asp(403) (metal coordination to L), and Asp(556) (hydrogen bonding of ATP or FAD ribose to L domain). Interestingly, the His(221) point mutant acted specifically as a cyclase without kinase activity. << Less

  J. Biol. Chem. 289:10620-10636(2014) [PubMed] [EuropePMC]

• Identification of human and rat FAD-AMP lyase (cyclic FMN forming) as ATP-dependent dihydroxyacetone kinases.

  Cabezas A., Costas M.J., Pinto R.M., Couto A., Cameselle J.C.

  Rat liver FAD-AMP lyase or FMN cyclase is the only known enzymatic source of the unusual flavin nucleotide riboflavin 4',5'-cyclic phosphate. To determine its molecular identity, a peptide-mass fingerprint of the purified rat enzyme was obtained. It pointed to highly related, mammalian hypothetica ... >> More

  Rat liver FAD-AMP lyase or FMN cyclase is the only known enzymatic source of the unusual flavin nucleotide riboflavin 4',5'-cyclic phosphate. To determine its molecular identity, a peptide-mass fingerprint of the purified rat enzyme was obtained. It pointed to highly related, mammalian hypothetical proteins putatively classified as dihydroxyacetone (Dha) kinases due to weaker homologies to biochemically proven Dha kinases of plants, yeasts, and bacteria. The human protein LOC26007 cDNA was used to design PCR primers. The product amplified from human brain cDNA was cloned, sequenced (GenBank Accession No. ), and found to differ from protein LOC26007 cDNA by three SNPs. Its heterologous expression yielded a protein active both as FMN cyclase and ATP-dependent Dha kinase, each activity being inhibited by the substrate(s) of the other. Cyclase and kinase activities copurified from rat liver extracts. Evidence supports that a single protein sustains both activities, probably in a single active center. Putative Dha kinases from other mammals are likely to be FMN cyclases too. Future work will profit from the availability of the structure of Citrobacter freundii Dha kinase, which contains substrate-interacting residues conserved in human Dha kinase/FMN cyclase. << Less

  Biochem. Biophys. Res. Commun. 338:1682-1689(2005) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Purification and characterization of triokinase from porcine kidney.

  Miwa I., Kito Y., Okuda J.

  In order to be able to use triokinase for the enzymatic assay of tissue glyceraldehyde, we purified the enzyme to homogeneity from porcine kidney and characterized its biochemical properties. The purification was performed by polyethylene glycol fractionation, anion exchange chromatography, hydrox ... >> More

  In order to be able to use triokinase for the enzymatic assay of tissue glyceraldehyde, we purified the enzyme to homogeneity from porcine kidney and characterized its biochemical properties. The purification was performed by polyethylene glycol fractionation, anion exchange chromatography, hydroxyapatite chromatography, hydrophobic chromatography, and gel filtration. The enzyme was purified 937-fold from the crude extract with an overall yield of 28%. It had a molecular weight of 122,000 and was a dimer composed of identical subunits. The optimal pH and optimal temperature were 7.0 and 60 degrees C, respectively. This enzyme was stable when incubated at pH 7.0 at 40 degrees C for 1 h in the presence of 0.1 mg/ml bovine serum albumin. No loss of activity occurred for at least 1 month when the enzyme was stored at 4 degrees C in the presence of 1 mM dithiothreitol and 15 mM NaN3 under N2. Only three compounds, i.e., D-glyceraldehyde, dihydroxyacetone, and glycolaldehyde, acted as the substrate of the enzyme, having Km's of 11, < 5, and 260 microM, respectively. The Km for ATP-Mg2+ was 68 microM. These results indicate that porcine kidney triokinase has properties advantageous for the glyceraldehyde assay using glyceraldehyde-3-phosphate dehydrogenase as a coupling enzyme. << Less

  Prep. Biochem. 24:203-223(1994) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Enzymes involved in fructose metabolism in lir and the glyceraldehyde metabolic crossroads.

  Sillero M.A., Sillero A., Sols A.

  Eur J Biochem 10:345-350(1969) [PubMed] [EuropePMC]