Colorless green ideas

Who among us hasn't wondered where, exactly, that other red sock has disappeared to, only to find that one's entire collection of white laundry now exhibits a decidedly pinkish tint? In this issue, Joel Cherry and coworkers at Novo-Nordisk (Bagsvaerd, Denmark) describe the directed evolution of a heme peroxidase (CiP), isolated from the inkcap mushroom Coprinus cinereus. CiP acts as a dye-transfer inhibitor in laundry detergent by decolorizing free dyes that have leached out of clothing, thereby preventing their reuptake by other garments. This paper represents far more than an end to the terror of the lone red sock, however. Cherry et al. combine protein variations made by both rational and empirical methods to increase the thermal and oxidative stability of CiP, an approach that has the potential to improve biocatalysts for a wide variety of applications.