An Escherichia coli K-12 auxotrophic derivative that grows if supplemented with pyridoxine, isoleucine, leucine, or alanine is described.

Separation of Neurospora mitochondrial outer membranes from the inner membrane/matrix fraction was effected by digitonin treatment and discontinuous density gradient centrifugation. The solubilization of four isoleucine-valine biosynthetic enzymes was studied as a function of digitonin concentration and time of incubation in the detergent. The kinetics of the appearance of valine biosynthetic f...

Glycyl dehydropeptides of alanine, phenylalanine, norvaline, norleucine, and or-aminobutyric acid, and N-acetyl dehydropeptides of these amino acids, tyrosine, valine, and leucine have been prepared (l-3). Although the glycyl dehydropeptides were found to be hydrolyzed by tissue extracts, the only enzymatically susceptible N-acetyl dehydropeptide was that of alanine (1). In an effort to acquire...