Enzyme responsible for complete oxidation of glucose to CO2 and water is present in:
Under aerobic conditions, pyruvate is taken up into mitochondria, and after oxidative decarboxylation to acetyl-CoA is oxidized to CO2 by the citric acid cycle.
Under anaerobic conditions, pyruvate is reduced by the NADH to lactate, catalyzed by lactate dehydrogenase.

(Ref: Harper Ed. 29th pg173, Ed 30th pg 172)
Cytosol
Mitochondria
Lysosomes
ER