<prompt> Blood samples for glucose estimation are collected in fluoride bulbstubes as fluride prevents glycolysis byinhibition ofEnolaseAldolaseGlucokinasePhosphofructokinase  <response>: Ans. a Enolase Ref. Harpers Illustrated 26th ed., 137; 27thCh. 18ENOLASE The step of glycolysis catalyzed by enolase involves dehydration, forming phosphoenolpyruvate. Enolase is inhibited by fluoride.- To prevent glycolysis in the estimation of glucose, blood is collected in tubes containing fluoride. The enzyme is also dependent on the presence of either Mg2 or Mn2. The phosphate of phosphoenolpyruvate is transferred to ADP by pyruvate kinase to generate, at this stage, two molecules of ATP per molecule of glucose oxidized. The product of the enzyme-catalyzed reaction, enolpyruvate, undergoes spontaneous nonenzymic isomerization to pyruvate and so is not available to undergo the reverse reaction. The pyruvate kinase reaction is thus also irreversible under physiologic conditions. EnzymeInhibitorPathway1.AconitaseFluoroacetateKrebs cycle2.L-KG dehydrogenaseArseniteKrebs cycle3.EnolaseFluorideGlycolysis4.Succinate dehydrogenaseMalonate oxaloacetateKrebs cycle5.Glyceradehyde-3 phosphateLactoacetate dehydrogenaseGlycolysis6.MOAIproniazid 7.Pyruvate dehydrogenaseArsenite 8.Carbonic anhydraseSulfanilamide 