UW-Madison researchers have developed a method for making cobalt-substituted protoporphyrins (CoPPIX), which could be useful in improving enzymatic reactions. Their process leverages E. coli BL21, which is grown in the presence of iron and cobalt along with a suitable medium (e.g., tryptone, yeast extracts, and autoinduction media containing a mixture of glucose and lactose). During culture, the cell optical density is monitored until a desired threshold is reached, at which time cobalt and delta-aminolevulanic acid are added to induce production of CoPPIX. The cobalt that is added can be in a variety of salt compositions (e.g., CoCl2) and the timing of addition with the delta-aminolevulanic acid can be synchronous or asynchronous. For incorporation of CoPPIX into a protein of interest, the protein can be overexpressed on a standard vector, with expression induction occurring before, during, or after addition of CoCl2. Cell growth can continue for 2-16 hours after induction. The result is an enzyme having CoPPIX incorporated therein.