The Anion-π Enzyme (IMAGE) Université de Genève Caption The anion-π enzyme consists of an electron-poor arene cofactor (grey stick representation) embedded within a protein (displayed as surface). Credit © free Usage Restrictions None 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.