Biotin in blood

A variety of biotin-requiring microorganisms have been used to assay biotin Saccharomyces cerevisiae (H6), Lactobacillus casei (S2), Lactobacillus arabinosus (now L. plantarum ATCC No. 8014) (W14), Micrococcus sodonensis (Al), Neurospora crassa (H10), and Rhizobium tri-folii (W7). None have been applied successfully for assaying biotin in biologic fluids. Because the flagellate Ochromoms danica had a specific and sensitive biotin requirement (A2), it was utilized as a reagent for biotin in blood, serum, urine, brain, and liver tissue (B3b). 

Wellenberg GJ, Banks JN. Enzyme linked sorbent assay to quantify d-biotin in blood. J Sci Fd Agric 1993 63 1-5. 

In general, the combined urinary and fecal excretion of biotin exceeds the dietary intake. It seems likely that the fecal excretion of biotin is an indication of intestinal synthesis, whereas urinary excretion is a reflection of the dietary intake. Published reports of normal values of biotin in blood vary too widely for diagnostic use without carefully controlled observations. 

Bioassays are generally sensitive enough to measure biotin in blood and urine. However, the bacterial bioassays (and perhaps the eukaryotic bioassays as well) suffer interference from unrelated substances and variable growth response to biotin analogues. Bioassays give conflicting results if biotin is bound to protein. 

A rapid avidin/biotin ELISA has been developed for the determination of bovine somatotropin in blood and milk (150). The method uses affinity-purified polyclonal antisera raised in rabbits to immobilize bovine somatotropin from... 

Miee treated with a nontoxie dose of a biotin-tagged OP called FP-biotin had FP-biotinylated albumin in blood and... 

Biotin forms part of several enzyme systems and is necessary for normal growth and body function. Biotin functions as a cofactor for enzymes involved in carbon dioxide fixation and transfer. These reactions are important in the metaboHsm of carbohydrates, fats, and proteins, as well as promotion of the synthesis and formation of nicotinic acid, fatty acids, glycogen, and amino acids (5—7). Biotin is absorbed unchanged in the upper part of the small intestine and distributed to all tissues. Highest concentrations are found in the Hver and kidneys. Little information is available on the transport and storage of biotin in humans or animals. A biotin level in urine of approximately 160 nmol/24 h or 70 nmol/L, and a circulating level in blood, plasma, or serum of approximately 1500 pmol/L seems to indicate an adequate supply of biotin for humans. However, reported levels for biotin in the blood and urine vary widely and are not a reHable indicator of nutritional status. 

The RDA for biotin has not been established. The requirement for biotin has been established as 30 to 100 pg/day. Biotin is produced by the gut microflora, which, it has been estimated, supplies half of our requirement. The rate of transport of free biotin by the gut cell is higher in the jejunum than in the ileum and is very low in the colon. Despite the low level of transport in the colon, it is apparently sufficient to allow supply by vitamin produced in the gut. The digestion of dietary proteins results in the release of the constituent amino acids and of biotin in the form of lysyl-biotin. Lysyl-biotin is further cleaved to lysine and biotin by biotinidase, an enzyme of the gut mucosa. The enzyme is present in milk and in the bloodstream as well, Biotin in human blood plasma occurs at a concentration of about 4 nM (Velazquez ef /, 1995). Nearly all of the biotin in human milk is free and not bound to proteins. Breast milk contains biotin at concentrations of about 25 nM (MiKik et al., 1997a),... 

Schrijver J, van Breederode N, van ben Berg H, Bitsch R. Biotin in whole blood by microbiological assay biotin in plasma or urine by RIA. In Fidanza F, ed. Nutritional status assessment A manual for population studies. London Chapman 8c Hall, 1991 296-303. 

PROP is caused by a deficiency of the mitochondrial enzyme, propionyl-CoA carboxylase (PCC) [7, 13]. The enzyme is composed of two subunits, an alpha and beta subunit, each encoded by a different gene, PCCA and PCCB, respectively [7]. The enzyme is biotin dependent with biotin binding to the alpha subunit [13, 14]. Deficiency of the enzyme results in the accumulation of propionyl-CoA and increased concentrations of free propionate in blood and urine. Methylcitrate and 3-hydroxypropionate are the... 

Dokusova OK and Krivoruchenko IV. The effect of biotin on blood cholesterol levels of atherosclerotic patients in idiopathic hyperlipidemia. Kardiologia 12 113 (1972). 

Mice treated with a nontoxic dose of a biotin-tagged OP called fluorophosphate (FP)-biotin had FP-biotinylated albumin in blood and muscle (Peeples et al., 2005). In vitro experiments identified the site in human albumin for covalent attachment of a variety of OPs as tyrosine 411 (Li et al., 2007). 

Odd-chain fatty acid accumulation is also a marker of biotin deficiency. The accumulation of odd-chain fatty acid is thought to result from PCC deficiency (Figure 3) the accumulation of propionyl-CoA likely leads to the substitution of a propionyl-CoA moiety for acetyl-CoA in the ACC reaction and to the incorporation of a three- (rather than two-) carbon moiety during fatty acid elongation. However, in comparison to lymphocyte PCC activity and urinary excretion of 3-hydroxyisovaleric acid, odd-chain fatty acids accumulate in blood lipids more slowly during biotin deficiency and return to normal more gradually after biotin repletion. 

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