A peroxisomal glycolate oxidase in the algaMougeotia.

Microbodies of the algaMougeotia were isolated in a linear sucrose gradient. The organelles, which moved to the density 1.24 g cm(-3), contained about 70% of the glycolate oxidase (EC 1.1.3.1) found in this alga. The enzyme oxidized glycolate, utilizing either oxygen or 2,6-dichlorophenolindophenol (DCPIP) as the electron acceptor. L-Lactate was an alternate substrate; almost no D-lactate was utilized. In the presence of O2, a Km of 415 μM was determined for glycolate, whereas the Km for L-lactate was about 5,000 μM. In the presence of DCPIP, lower concentrations of glycolate and L-lactate were sufficient to obtain the highest rates of enzyme activity.