Biotin-containing proteins

Avidin was the first commercially available recombinant protein (1997) to be derived from a transgenic system (corn seed) for use in medical applications [285, 286, 291]. As it forms strong, non-covalent bonds with biotin, avidin is used in medical and biochemical diagnostic kits for the detection of biotin-containing proteins and nucleic acids. Transgenic corn which accumulated avidin was developed jointly by... 

This enzyme is a biotin-containing protein which catalyses a rate-limiting step in gluco-neogenesis from pyruvate. It can be assayed by u.v. spectroscopy using malate dehydrogenase in an indicator reaction [585] or radiochemically by incorporation of C labelled bicarbonate into oxalacetate stabilised by conversion to its 2,4-dinitrophenyl-hydrazone [586]. 

It is continuously recycled as part of the biotin-containing protein s metabolism. 

ACETYL-CoA CARBOXYLASE AND BIOTIN-CONTAINING PROTEINS IN CARROT SOMATIC EMBRYOGENESIS... 

Biocytin is e-N-biotinyl-L-lysine, a derivative of D-biotin containing a lysine group coupled at its e-amino side chain to the valeric acid carboxylate. It is a naturally occurring complex of biotin that is typically found in serum and urine, and probably represents breakdown products of recycling biotinylated proteins. The enzyme biotinidase specifically cleaves the lysine residue and releases the biotin component from biocytin (Ebrahim and Dakshinamurti, 1986, 1987). 

The following protocol is a suggested method for modifying sulfhydryl-containing proteins with biotin-BMCC. Some optimization of biotinylation levels may have to be done for particular applications. 

A suggested protocol for the use of biotin-HPDP in the modification of sulfhydryl-containing proteins follows. Similar procedures may be used when biotinylating other molecules. 

Figure 28.12 Sulfo-SBED first is used to label a bait protein through reaction of the sulfo-NHS ester with available amine groups on the protein, yielding an amide bond linkage. This labeled bait protein then is added to a sample containing proteins that potentially could interact with the bait. After an incubation period, the sample is exposed to UV light to photoactivate the phenyl azide group. This reaction causes any interacting prey proteins to be crosslinked with the bait protein, forming a complex containing a biotin affinity tag.

Acetyl CoA carboxylase Fatty acid synthesis of raw eggs (contain avidin, a biotin-binding protein)... 

---