Publications

• Removal of phosphoglycolate in hyperthermophilic archaea.

  Michimori Y., Izaki R., Su Y., Fukuyama Y., Shimamura S., Nishimura K., Miwa Y., Hamakita S., Shimosaka T., Makino Y., Takeno R., Sato T., Beppu H., Cann I., Kanai T., Nunoura T., Atomi H.

  Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurren ... >> More

  Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurrence of 2-phosphoglycolate salvage is linked to the CBB cycle, and in particular, the C2 pathway to the CBB cycle and oxygenic photosynthesis. Here, we examined 2-phosphoglycolate salvage in the hyperthermophilic archaeon <i>Thermococcus kodakarensis</i>, an obligate anaerobe that harbors a Rubisco that functions in the pentose bisphosphate pathway. <i>T. kodakarensis</i> harbors enzymes that have the potential to convert 2-phosphoglycolate to glycine and serine, and their genes were identified by biochemical and/or genetic analyses. 2-phosphoglycolate phosphatase activity increased 1.6-fold when cells were grown under microaerobic conditions compared to anaerobic conditions. Among two candidates, TK1734 encoded a phosphatase specific for 2-phosphoglycolate, and the enzyme was responsible for 80% of the 2-phosphoglycolate phosphatase activity in <i>T. kodakarensis</i> cells. The TK1734 disruption strain displayed growth impairment under microaerobic conditions, which was relieved upon addition of sodium sulfide. In addition, glycolate was detected in the medium when <i>T. kodakarensis</i> was grown under microaerobic conditions. The results suggest that <i>T. kodakarensis</i> removes 2-phosphoglycolate via a phosphatase reaction followed by secretion of glycolate to the medium. As the Rubisco in <i>T. kodakarensis</i> functions in the pentose bisphosphate pathway and not in the CBB cycle, mechanisms to remove 2-phosphoglycolate in this archaeon emerged independent of the CBB cycle. << Less

  Proc Natl Acad Sci U S A 121:e2311390121-e2311390121(2024) [PubMed] [EuropePMC]

  This publication is cited by 21 other entries.

• Comparative characterization of Aedes 3-hydroxykynurenine transaminase/alanine glyoxylate transaminase and Drosophila serine pyruvate aminotransferase.

  Han Q., Li J.

  This study describes the comparative analysis of two insect recombinant aminotransferases, Aedes aegypti 3-hydroxykynurenine (3-HK) transaminase/alanine glyoxylate aminotransferase (Ae-HKT/AGT) and Drosophila melanogaster serine pyruvate aminotransferase (Dm-Spat), which share 52% identity in thei ... >> More

  This study describes the comparative analysis of two insect recombinant aminotransferases, Aedes aegypti 3-hydroxykynurenine (3-HK) transaminase/alanine glyoxylate aminotransferase (Ae-HKT/AGT) and Drosophila melanogaster serine pyruvate aminotransferase (Dm-Spat), which share 52% identity in their amino acid sequences. Both enzymes showed AGT activity. In addition, Ae-HKT/AGT is also able to catalyze the transamination of 3-HK or kynurenine with glyoxylate, pyruvate or oxaloacetate as the amino acceptor. Kinetic analysis and other data suggest that Ae-HKT/AGT plays a critical role in mosquito tryptophan catabolism by detoxifying 3-HK and that Dm-Spat is primarily involved in glyoxylate detoxification. << Less

  FEBS Lett. 527:199-204(2002) [PubMed] [EuropePMC]

  This publication is cited by 19 other entries.

• Species distribution and properties of hepatic phenylalanine (histidine):pyruvate aminotransferase.

  Minatogawa Y., Noguchi T., Kido R.

  Hepatic phenylalanine(histidine):pyruvate aminotransferase activity is much higher in the mouse and rat than in other animal species (human, guinea-pig, rabbit, pig, dog and chicken). The activity is elevated in the mouse and rat by the injection of glucagon but not in other species (guinea-pig, r ... >> More

  Hepatic phenylalanine(histidine):pyruvate aminotransferase activity is much higher in the mouse and rat than in other animal species (human, guinea-pig, rabbit, pig, dog and chicken). The activity is elevated in the mouse and rat by the injection of glucagon but not in other species (guinea-pig, rabbit and chicken). The enzyme was purified from the mitochondrial fraction of mouse liver to homogeneity as judged by polyacrylamide disc gel electrophoresis in the presence of dodecylsulphate. With histidine as amino donor, the enzyme was active with pyruvate, oxaloacetate and hydroxypyruvate as amino acceptors but not with 2-oxoglutarate. Effective amino donors were histidine, phenylalanine and tyrosine with pyruvate, and methionine, serine and glutamine with phenylpyruvate. The apparent Km for histidine was about 6.9 mM with pyruvate and that for pyruvate was 21 mM with histidine. The enzyme is probably composed of two identical subunits with a molecular weight of approximately 40000. The pH optimum was near 9.0. Isoelectric focusing of the purified enzyme resulted in the detection of four forms with pI 6.0, 6.2, 6.5 and 6.7, respectively, all of which were responsive to glucagon. These four forms were nearly identical with the purified enzyme before the focusing with respect to physical and enzymic properties. A possible mechanism of this multiplicity is discussed. << Less

  Hoppe Seylers Z Physiol Chem 358:59-67(1977) [PubMed] [EuropePMC]