Chemical segregation of complex organic O-bearing species in Orion KL.

We investigate the chemical segregation of complex O-bearing species (including the largest and most complex ones detected to date in space) towards Orion KL, the closest high-mass star-forming region. The molecular line images obtained using the ALMA science verification data reveal a clear segregation of chemically related species depending on their different functional groups. We map the emission of CHOH, HCOOCH, CHOCH, CHOCH, CHCOOCH, HCOOCHCH, CHCHOCH, HCOOH, OHCHCHOH, CHCOOH, CHCHOH, CHOCHOH, OHCHCHO, and CHCOCH with ~1.

Searching for trans ethyl methyl ether in Orion KL.

We report on the tentative detection of trans ethyl methyl ether (tEME), t-CHCHOCH, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CHCHCHOH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data.

Photoaffinity labeling of protoporphyrinogen oxidase, the molecular target of diphenylether-type herbicides.

Diphenylether-type herbicides are extremely potent inhibitors of protoporphyrinogen oxidase, a membrane-bound enzyme involved in the heme and chlorophyll biosynthesis pathways. Tritiated acifluorfen and a diazoketone derivative of tritiated acifluorfen were specifically bound to a single class of high-affinity binding sites on yeast mitochondrial membranes with apparent dissociation constants of 7 nM and 12.5 nM, respectively.

Purification and properties of protoporphyrinogen oxidase from the yeast Saccharomyces cerevisiae. Mitochondrial location and evidence for a precursor form of the protein.

Protoporphyrinogen oxidase, the molecular target of diphenylether-type herbicides, was purified to homogeneity from yeast mitochondrial membranes and found to be a 55-kDa polypeptide with a pI of 8.5 and a specific activity of 40,000 nmol of protoporphyrin/h/mg of protein at 30 degrees C. The Michaelis constant (Km) for protoporphyrinogen IX was 0.