Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An androgen affinity column was synthesized by covalently linking 3-oxo-17beta-hydroxy-5alpha-androstan-17alpha-(6-hexanoic acid) to cyanogen bromide activated Sepharose through a dipropyldiamine side arm. This column was designed to recover androphilic proteins from homogenates rich in nonspecific esterases. An extract of rat epididymis was adsorbed on the affinity column after partial purification by ammonium sulfate precipitation. The column was washed with 1 M KCl and the androgen binding protein eluted with 17beta-hydroxy-5alpha-androstan-3-one resulting in a 1,100-fold increase in specific activity. This protein had the same mobility on polyacrylamide gels and the same estimated molecular weight (135,000 daltons by gel filtration) as androgen binding protein in the original extract. By contrast, electrophoresis on sodium dodecyl sulfate containing gels yielded 2 bands with estimated molecular weights of 42,000 and 47,000 daltons. These observations are consistent with a subunit structure for rat epididymal androgen binding protein.
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PMID:A novel affinity column for isolation of androgen binding protein from rat epididymis. 89 61

Biotinylated insulins are bivalent molecules having the ability to bind to insulin receptors on the one hand and to "avidins" on the other. In order to be useful as ligands for insulin receptor isolation, biotinylated insulins must be developed that have the capacity to bind simultaneously to both and insulin receptor. The present investigation addresses this problem. A series of biotinylated and dethiobiotinylated insulins has been prepared in which the distance between the biotin carboxyl group and the insulin varies from 7 to 20 atoms. These compounds form complexes with succinoylavidin. The dissociation rates (K-1) of these complexes have been determined from the [14C]biotin exchange assay. The dissociation kinetics of most of these complexes are biphasic, and the kinetic constants reported are those corresponding to the slow rate. Ligands containing dethiobiotin dissociate more rapidly than the corresponding biotin derivatives. The interposition of a spacer arm substantially decreases the rate of dissociation. The [14C]biotin exchange assay could not be used with streptavidin complexes of the above ligand since biotin dissociates more rapidly from streptavidin than from succinoylavidin. However, the relative dissociation rates of a series of ligands could be determined and were as follows: 6-(dethiobiotinylamido)-hexanoic acid greater than dethiobiotinyl-A1-insulin greater than biotinylinsulin greater than biotinyl-A1-insulin greater than biotinyl-A2-insulin. Dethiobiotin and its amide failed to form complexes with streptavidin. The affinity of the ligands for insulin receptors was determined by measuring their ability to stimulate 14CO2 formation from [1-14C]glucose in rat epididymal adipocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ligands for insulin receptor isolation. 638 May 71