The flavin content of tissues and tissue homogenates has been reported from time to time (see, for example, (l)), but quantitative information on the partition of flavins in more defined preparations used in the study of electron transport systems is generally meager (cj. (2)). Recently, Ziegler, Green, and Doeg (3) claimed that beef heart mitochondria contain only flavin adenine dinucleotide i...

1. The inducible p-hydroxybenzoate hydroxylase of Pseudomonas putidu which catalyzes the hydroxylation of P-hydroxybenzoate to protocatechuate has been obtained in crystalline form as a protein homogeneous upon ultracentrifugation and electrophoresis. The molecular weight is estimated to be 83,600. 2. The enzyme contains approximately 1 mole of flavin adenine dinucleotide per mole of protein. R...

The rate of transport of L-amino acids by Saccharomyces cerevisiae epsilon 1278b increased with time in response to nitrogen starvation. This increase could be prevented by the addition of ammonium sulfate or cycloheximide. A slow time-dependent loss of transport activity was observed when ammonium sulfate (or ammonium sulfate plus cycloheximide) was added to cells after 3 h of nitrogen starvat...

Diazotized 3-aminopyridine adenine dinucleotide has been found to modify four sulfhydryl groups per molecule of enzyme during the complete inactivation of yeast alcohol dehydrogenase. The reaction of sulfhydryl groups was indicated by titration studies with 5,5-dithiobis(2-nitrobenzoic acid) as well as isolation and quantitation of the cysteinyl derivative released by acid hydrolysis of the mod...

The time course of thioredoxin-mediated reductive activation of isolated Zea mays nicotinamide adenine dinucleotide phosphatemalate dehydrogenase is highly sigmoidal in nature. We examined the factors affecting these kinetics, including the thiol-disulfide status of unactivated and activated forms of the enzyme. The maximum steady rate of activation was increased, and the length of the lag in a...