Fatty acid methyl esters are the major radioactive lipid products obtained after incubation of rat lung membranes with [methyl-3H or 14C]S-adenosylmethionine. Evidence which suggests an enzymatic transmethylation includes: time and protein dependence, lack of reaction at 0 degrees C or with heat-denatured membranes, an apparent affinity for S-adenosylmethionine of about 1 microM, inhibition by ...

Strategic replacement of protons with fluorine atoms or functional groups fluorine-containing fragments has proven a powerful strategy to optimize the activity therapeutic compounds. For this reason, synthetic chemistry organofluorides been subject intense development and innovation for many years. By comparison, literature on biocatalysis still makes slim chapter. Herein we introduce S-adenosy...

A cyclic sulfonium compound, S-methyl homocysteine thiolactone (SMHT), is formed from methionine during in vitro tRNA aminoacylation catalyzed by Escherichia coli methionyl-tRNA synthetase. The mechanism of SMHT formation involves enzymatic deacylation of Met-tRNA (k = 0.06 s-1) and, to a lesser extent, Met-AMP (k = 0.02 s-1). Cyclization of methionine, reminiscent of cyclization of homocystein...

Exposing etiolated pea seedlings to ethylene which inhibited the activity of arginine decarboxylase and S-adenosylmethionine decarboxylase caused an increase in the level of cadaverine. The elevated level of cadaverine resulted from an increase in lysine decarboxylase activity in the tissue exposed to ethylene. The hormone did not affect the apparent K(m) of the enzyme, but the apparent V(max) ...

Z. Naturforsch. 44c, 55 — 58 (1989); received August 1, 1988 Abutilon theophrasti, Lycopersicon esculentum, S-Adenosylmethionine Decarboxylase, Arginine Decarboxylase. Ornithine Decarboxylase, Spermidine Synthase Inhibitors of enzymes involved in polyamine biosynthesis which stop the growth of bacteria, fungi and animal cell systems were analyzed for their potential to interfere with plant cell...

Polyamines are widespread distributed all over in living organisms. In Thalassiosira pseudonana 10 N-aminopropyl transferase like nucleotide sequences exists. It is assumed that these sequences are involved in the biomineralization of the diatom shell. The cDNA of the sequences were cloned, recombinant overexpressed and assayed with decarboxylated S-adenosylmethionine and several radioactive la...

Pyruvate formate-lyase (formate acetyltransferase; EC 2.3.1.54) of Escherichia coli cells is post-translationally interconverted between inactive and active forms. Conversion of the inactive to the active form is catalyzed by an Fe2+-dependent activating enzyme and requires adenosylmethionine and dihydroflavodoxin. This process is shown here to introduce a paramagnetic moiety into the structure...

Acyl homoserine lactones (acyl-HSLs) are important intercellular signaling molecules used by many bacteria to monitor their population density in quorum-sensing control of gene expression. These signals are synthesized by members of the LuxI family of proteins. To understand the mechanism of acyl-HSL synthesis we have purified the Pseudomonas aeruginosa RhlI protein and analyzed the kinetics of...

Subtilosin A is a 35-residue, ribosomally synthesized bacteriocin encoded by the sbo-alb operon of Bacillus subtilis. It is composed of a head-to-tail circular peptide backbone that is additionally restrained by three unusual thioether bonds between three cysteines and the α-carbon of one threonine and two phenylalanines, respectively. In this study, we demonstrate that these bonds are synthesi...