NO NEWS IS GOOD-NEWS

The recent determination of the crystal structure of microsomal cytoch rome P450 reductase, a diflavin protein that shuttles electrons from N ADPH to the P450 heme, represents a significant advance towards the un derstanding of cytochromes P450, A similar advance was made in a relat ed enzyme system, nitric oxide synthase (NOS), The crystal structure o f the NOS heme domain reveals a very different architecture to that ob served in P450s and offers significant insight into the production of nitric oxide, one of nature's most important regulatory molecules.