Measurement of biotin in plasma and urine has been stimulated by recent descriptions of inborn errors of biotin metabolism and by newly recognized causes of biotin deficiency. Biotin determination in physiologic fluids to document these conditions has been hindered by lack of a widely useable assay. This paper presents a method which employs tritium-labelled biotin, avidin, and nitrocellulose f...

A biotin-degrading particulate system has been obtained by sonic rupture of a soil pseudomonad which grows on d-biotin as sole source of carbon, nitrogen, and sulfur. Investigation of the catabolism of l*C-biotin and its sulfoxides in this system has revealed the following. Degradation of biotin to CO2 is enhanced in the bufferwashed particulate preparations by addition of adenosine triphosphat...

Biotin is an essential micronutrient that acts as a co-factor for biotin-dependent metabolic enzymes. In bacteria, the supply of biotin can be achieved by de novo synthesis or import from exogenous sources. Certain bacteria are able to obtain biotin through both mechanisms while others can only fulfill their biotin requirement through de novo synthesis. Inability to fulfill their cellular deman...

Biotin synthase, encoded by the bio2 gene in Arabidopsis, catalyzes the final step in the biotin biosynthetic pathway. The development of radiochemical and biological detection methods allowed the first detection and accurate quantification of a plant biotin synthase activity, using protein extracts from bacteria overexpressing the Arabidopsis Bio2 protein. Under optimized conditions, the turno...

Biotin is an essential cofactor of carboxylase enzymes in all kingdoms of life. The vitamin is produced by many prokaryotes, certain fungi, and plants. Animals depend on biotin uptake from their diet and in humans lack of the vitamin is associated with serious disorders. Many aspects of biotin metabolism, uptake, and intracellular transport remain to be elucidated. In order to characterize the ...

Biotin administration to biotin-deficient rats enhanced protein synthesis. Time sequence studies indicated that RNA synthesis was stimulated as early as 1 hour after biotin administration to the deficient rat. The synthesis of RNA of liver was stimulated by biotin administration. Nuclear RNA isolated from biotin-injected rats was more active in a protein-synthesizing system in vitro than a simi...

1. Yeast cells grown in the presence of an unknown radioactive biotin vitamer produced by Penicillium chrysogenum incorporated the vitamer into the newly synthesized biotin. 2. The biotin was isolated as the avidin-biotin complex and after hydrolysis the biological activity and radioactivity were shown to be coincidental. 3. The specific activity of the biotin was identical with that of the pim...

Besides its role as a carboxylase prosthetic group, biotin has important effects on gene expression. However, the molecular mechanisms through which biotin exerts these effects are largely unknown. We previously found that biotin increases pancreatic glucokinase expression. We have now explored the mechanisms underlying this effect. Pancreatic islets from Wistar rats were treated with biotin, i...

The plasma of laying hens contains a specific biotin-binding protein that appears to be identical with an egg-yolk biotin-binding protein. Both proteins are saturated with biotin and require elevated temperatures to effect the exchange of [14C]biotin for the protein-bound vitamin. The heat-exchange curve in each case is the same and differs sharply from that of avidin, the egg-white biotin-bind...