Presence of a plant-like proton-pumping pyrophosphatase in acidocalcisomes of Trypanosoma cruzi.
Authors:Scott DA, de Souza W, Benchimol M, Zhong L, Lu HG, Moreno SN, Docampo R
Journal:J Biol Chem
PubMed ID:9705361
'The vacuolar-type proton-translocating pyrophosphatase (V-H+-PPase) is an enzyme previously described in detail only in plants. This paper demonstrates its presence in the trypanosomatid Trypanosoma cruzi. Pyrophosphate promoted organellar acidification in permeabilized amastigotes, epimastigotes, and trypomastigotes of T. cruzi. This activity was stimulated by K+ ions and was inhibited by Na+ ... More
A broadly applicable continuous spectrophotometric assay for measuring aminoacyl-tRNA synthetase activity.
Authors:Lloyd AJ, Thomann HU, Ibba M, Söll D
Journal:Nucleic Acids Res
PubMed ID:7659511
'We describe a convenient, simple and novel continuous spectrophotometric method for the determination of aminoacyl-tRNA synthetase activity. The assay relies upon the measurement of inorganic pyrophosphate generated in the first step of the aminoacylation of a tRNA. Pyrophosphate release is coupled to inorganic pyrophosphatase, to generate phosphate, which in turn ... More
Thiamin biosynthesis in Escherichia coli. Identification of this thiocarboxylate as the immediate sulfur donor in the thiazole formation.
ThiFSGH and ThiI are required for the biosynthesis of the thiazole moiety of thiamin in Escherichia coli. The overproduction, purification, and characterization of ThiFS and the identification of two of the early steps in the biosynthesis of the thiazole moiety of thiamin are described here. ThiS isolated from E. coli ... More
AcsD catalyzes enantioselective citrate desymmetrization in siderophore biosynthesis.
Authors:Schmelz S, Kadi N, McMahon SA, Song L, Oves-Costales D, Oke M, Liu H, Johnson KA, Carter LG, Botting CH, White MF, Challis GL, Naismith JH,
Journal:Nat Chem Biol
PubMed ID:19182782
Bacterial pathogens need to scavenge iron from their host for growth and proliferation during infection. They have evolved several strategies to do this, one being the biosynthesis and excretion of small, high-affinity iron chelators known as siderophores. The biosynthesis of siderophores is an important area of study, not only for ... More
A spectrophotometric method to measure enzymatic activity in reactions that generate inorganic pyrophosphate.
Authors:Upson RH, Haugland RP, Malekzadeh MN, Haugland RP
Journal:Anal Biochem
PubMed ID:8954523
This paper describes a spectrophotometric assay that can measure the inorganic pyrophosphate produced from various enzymatic reactions. This is a coupled assay in which the addition of inorganic pyrophosphatase initially cleaves the pyrophosphate into two molecules of phosphate. The phosphate is then detected by the conversion of 2-amino-6-mercapto-7-methylpurine ribonucleoside to ... More