The primary sequence of the cytochrome subunit of the flavocytochrome p-cresol methylhydroxylase has been determined, as has the sequence of the first 52 amino acids of the flavoprotein subunit. X-ray crystallographic data at 3 A resolution have been fitted to these data and much of the tertiary structure has been unravelled. The rest of the sequence is being determined by DNA sequencing. The reversible dissociation of the flavocytochrome into subunits has been extensively investigated, as has its kinetic mechanism, using flash photolysis, stopped-flow, and steady- state kinetic methods. The reaction sequence catalyzed by the enzyme has been shown to include a vinyl derivative. The biochemical events underlying the neurotoxicity of MPTP, a contaminant in an illicit meperidine analog, has been determined and in vivo toxicity correlated with enzymological data. A new metabolite carrier which pumps MPP+, the oxidation product of MPTP, into the mitochondrial matrix, has been discovered and partially characterized. Extensive kinetic studies have been completed on salicylate hydroxylase, using a novel procedure to isolate the enzyme. The kinetic and molecular characteristics of an "inner" and an "outer" carnitine acyltransferase have been compared and peroxisomes shown to be the likely source of the the outer enzyme.
