This picture shows one of the steps of heme synthesis. In this step two propanoate groups of coproporphyrinogen III are decarboxylated to form protoporphyrinogen IX. The enzyme that catalyses this step is an oxidase. Oxidase enzymes catalyze the removal of hydrogen in the presence of oxygen to form water or hydrogen peroxdide.
So, will a water molecule form in this step? 2H+ will come from the two carboxylate groups and oxygen will combine with it to form water. Will a water molecule form in this way?