Glyoxalase metabolism

The pathway map below for Theileria is same as the glyoxalase metabolism pathway of Plasmodium falciparum and Toxoplasma gondii. In P. falciparum, D-lactate is produced in addition to L-lactate. The stereo-specificity of lactate dehydrogenase suggests the possibility of D-lactate being produced from methylglyoxal. In glycolysis, one of the intermediates is glycerone phosphate (dihydroxyacetone phosphate). The conversion of it to methylglyoxal, a toxic product can take place either spontaneously or by the action of enzyme methylglyoxal synthase in various organisms. In P. falciparum, there are no genes for methylglyoxal synthase identified and no enzymatic activity was experimentally detected. This suggests that this reaction takes place spontaneously. The genes for glyoxalase-I and glyoxalase-II are present in P. falciparum genome and their activities are also experimentally detected with parasite having 2-3 fold higher specific activities. The presence of different kinetic properties between enzymes from parasite material and from that of erythrocytes was also observed [1]. The ortholog for the enzyme glyoxalase I present in P. falciparum and T. gondii is missing in Theileria and Babesia, although ortholog of glyoxalase II is present. It is yet to be experimentally validated whether this pathway of production of D-lactate from methylglyoxal is present in Theileria and Babesia.

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Sources and fates of metabolites