Putting a C in Cytochrome Cytochrome P450 enzymes oxidize hydrocarbons using a highly reactive iron oxo intermediate. Much research has focused on tuning the protein structure to broaden the range of hydrocarbons that can be functionalized. Coelho et al. (p. 307 , published online 20 December; see the Perspective by Narayan and Sherman ) substituted a carbene source for the oxygen to make a P450 mutant a cyclopropanation catalyst whereby a carbon fragment is transferred in place of oxygen. Though carbene activation by iron is chemically analogous to the native oxygen activation pathway, the overall reaction is completely different from any known enzymatic transformation.

Loyalty has, over the past decade, become a crucial construct in marketing, and particularly in the burgeoning field of customer relationship management. This paper shows that customer loyalty can be explained to a substantial degree by customer satisfaction, trust, and communication, and shows the direct and indirect effects among those constructs and other constructs in an extension of the European Customer Satisfaction Index (ECSI) model. Both ECSI model and the extended model are estimated with data from a survey carried out among customers of the banking sector. Within the limitations of the study, the theoretical and managerial implications of these findings are discussed.

Genetically encoded catalysts for non-natural chemical reactions will open new routes to sustainable production of chemicals. We designed a unique serine-heme ligated cytochrome “P411” that catalyzes efficient and selective carbene transfers from diazoesters to olefins in intact Escherichia coli cells. The mutation C400S in cytochrome P450BM3 gives a signature ferrous-CO Soret peak at 411 nm, abolishes monooxygenation activity, raises the resting state FeIII/II reduction potential, and significantly improves NAD(P)H-driven cyclopropanation activity.

The development of new catalytic methods to functionalize carbon-hydrogen (C-H) bonds continues to progress at a rapid pace due to the significant economic and environmental benefits of these transformations over traditional synthetic methods. In nature, enzymes catalyze regio-and stereoselective C-H bond functionalization using transformations ranging from hydroxylation to hydroalkylation under ambient reaction conditions. The efficiency of these enzymes relative to analogous chemical processes has led to their increased use as biocatalysts in preparative and industrial applications. Furthermore, unlike small molecule catalysts, enzymes can be systematically optimized via directed evolution for a particular application and can be expressed in vivo to augment the biosynthetic capability of living organisms. While a variety of technical challenges must still be overcome for practical application of many enzymes for C-H bond functionalization, continued research on natural enzymes and on novel artificial metalloenzymes will lead to improved synthetic processes for efficient synthesis of complex molecules. In this critical review, we discuss the most prevalent mechanistic strategies used by enzymes to functionalize non-acidic C-H bonds, the application and evolution of these enzymes for chemical synthesis, and a number of potential biosynthetic capabilities uniquely enabled by these powerful catalysts.

Nitrogen activation: Though P450 enzymes are masters of oxygen activation and insertion into CH bonds, their ability to use nitrogen for the same purpose has so far not been explored. Engineered variants of cytochrome P450BM3 have now been found to catalyze intramolecular CH aminations in azide substrates. Mutations to two highly conserved residues significantly increased this activity.