Toxin production in a large number of Pyrenophora teres isolates have been investigated. During fungal growth, the pH of the medium decreases from 6.5 to about 3.0. Aspergillomarasmine A is the major toxin excreted into the culture medium. Nonenzymatic acid-catalyzed conversion of aspergillomarasmine A to anhydroaspergillomarasmine A proceeds at low pH and is prevented by repeated titration of ...

A preceding paper described the characteristics of the isolated enzyme system, prepared from ox liver acetone powder, which catalyzes the conversion of citrulline and aspartic acid to arginine and malic acid. It was shown that the fundamental requirements for arginine synthesis from citrulline are aspartic acid, Mg++, and adenosine triphosphate (ATP), the latter as a reactant in substrate conce...

Wzx belongs to a family of membrane proteins involved in the translocation of isoprenoid lipid-linked glycans, which is loosely related to members of the major facilitator superfamily. Despite Wzx homologs performing a conserved function, it has been difficult to pinpoint specific motifs of functional significance in their amino acid sequences. Here, we elucidate the topology of the Escherichia...

In previous investigations imidazoleacetic acid was shown to be quantitatively converted to formylaspartic acid by a partially purified enzyme preparation obtained from Pseudomonas sp. that requires DPNH’ and oxygen (2, 3). An intermediate in this process was isolated from the incubation mixture with highly purified enzyme preparations and was characterized as N-formimino-L-aspartic acid (4). E...

Lockhart & Abraham (1956) found that two compounds which appeared to be aspartyl-lysine and aspartyl(isoleucyl)-lysine respectively were formed when bacitracin A was hydrolysed with 11 Nhydrochloric acid at 800. The aspartic acid residue in these compounds had the L-configuration and was linked to the e-amino group of L-lysine. However, both compounds carried a net positive charge at pH 7 and t...