3) This paper as originally submitted to the Editor cited more than 100 references, which occupied fully one-third of the paper. In order to meet the space criteria of Accounts, we have chosen, where possible, to cite only recent references. A recent monograph gives an excellent up-to-date review of many areas touched upon here. Cytochrome P-450: Structure, Mechanism and Biochemistry, 2nd ed.; Ortiz de Montellano, P. R., Ed.; Plenum Press: New York, 1995. (4) Even the trivial names of porphyrins are frequently complex. In this review the major porphyrins are abbreviated as follows: TPP ) mesotetraphenylporphyrin (2a) etc. as shown for structures 2-14.Teddy G. Traylor (1925Traylor ( -1993 never graduated from high school, but after the war, where he served in the Merchant Marine, he received his Ph.D. at UCLA with Saul Winstein and then was a postdoctoral fellow with Paul Bartlett at Harvard. He was the first organic chemist hired at UCSD, where he was a pioneer in organometallic chemistry. Teddy was the first to publish papers on superstructured porphyrins, and his research on oxygen binding and P-450 chemistry was seminal for the past two decades. His love of chemistry was surpassed only by his love of life. We are sorry that he is not with us to still enjoy them. David Dolphin was born in London, England, at the beginning of the Second World War. After obtaining his undergraduate and graduate degrees at the University of Nottingham, he was a postdoctoral fellow with R. B. Woodward at Harvard and then joined the faculty there in 1966. In 1973 he joined the University of British Columbia, where he has been acting Dean of Science and is the NSERC/ QLT Industrial Research Professor in Photodynamic Technology. He is also the V.P. of Technology Development at QLT PhotoTherapeutics, a Vancouver-based biotechnology company that is the world leader in photodynamic therapy. Lily Y. Xie was born in Chongqing, People's Republic of China. She received her B.Sc. degree at Peking University in 1983 and her Ph.D. in 1990 at the University of British Columbia (UBC) under the direction of Brian R. James. She worked as a postdoctoral fellow with David Dolphin at UBC and then with Alison Butler at the

No abstract

No abstract

with the known properties of Compounds I of catalase and peroxidase leads us to propose that these forms of the enzymes contain a ir-cation radical of the heme prosthetic group. METHODSThe techniques for bromine oxidations, controlled potential electrolysis, coulometry, and for optical and esr measurements (as well as for purification and preparation of materials) have been described (4). For anion-transfer reactions, a quartz esr tube was attached to an ampoule with two side arms, one of which contained a degassed solution of [Co(III) (Et)8P]2+ 2Br-in chloroform and the other dry AgCl04 isolated by a fritted disc. After the spectrum of the bromide salt was obtained, the solution was shaken in the AgCl04 compartment to form the [Co(III)(Et)8P]2+ 2C104-salt. Relative concentrations of free radicals were determined by double integration by computer of the first-derivative spectra obtained under comparable experimental conditions. The mass spectrum was recorded on an AEI MS-9 mass spectrometer operating at 70 eV, and a source temperature of 2500C. The nuclear magnetic resonance (nmr) spectra were measured in chloroform and recorded on a Varian HA-100 spectrometer, with tetramethylsilane as internal reference. Attempts to oxidize ferric porphyrins to a formal Fe(V) oxidation state were unsuccessful due to solvent breakdown encountered at the high potentials required [>1.5 V vs. aqueous saturated calomel electrode (see) ]. RESULTS