Artificial Metalloenzyme (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption This is a graphic of an artificial metalloenzyme. Within the protein (grey) is a porphyrin (red), a component of natural heme proteins, with iridium as the active site (purple). The enzyme converts the molecules at the top to those at the bottom by reaction at a carbon-hydrogen bond (left) and carbon-carbon double bond (right), respectively. Credit John Hartwig Group/Berkeley Lab and UC Berkeley Usage Restrictions All rights reserved. Editorial use only. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.