Glycocholic acid

When all but a small portion of the solution of the pigments has run through develop the chromatogram , i.e. separate the zones by washing with a 4 1 mixture of petroleum ether and benzene. Check too great extension of the zones by adding petrol ether (boiling point 30-50°). 

Now wash with petrol ether, dry with suction in a current of C02, push out the column with a suitable glass rod and cut the various zones apart. 

Dissolve the pigments with ether containing a little methanol and examine the absorption spectrum. 

These simple operations constitute a clear demonstration of the possibilities of the method, the coloured zones of the column forming a beautiful picture of its efficiency.1 

For the preparation of chlorophyll in the practical class see the procedure described by Willstatter and Stoll on pages 133 and 138 of their book. 

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Mammalian bile contains sodium salts of conjugated bile acids, e.g. glycocholic acid and taurocholic acid, in which cholic acid is combined (amide linkage) with glycine and taurine respectively. 

Bile acids, which exist mainly as bile salts, are polar carboxylic acid derivatives of cholesterol that are important in the digestion of food, especially the solubilization of ingested fats. The Na and salts of glycocholic acid and tauro-cholic acid are the principal bile salts (Ligure 25.41). Glycocholate and tauro-cholate are conjugates of cholic acid with glycine and taurine, respectively. 

FIGURE 25.41 Cholic acid, a bile salt, is synthesized from cholesterol via 7o -hydroxy-cholesterol. Conjugation with taurine or glycine produces taurocholic acid and glycocholic acid, respectively. Taurocholate and glycocholate are freely water-soluble and are highly effective detergents. 

Glyko-cholsaure, /. glycocholic acid, -gallus-silure. /. glucogallic acid. 

These general observations have been confirmed in PAMPA measurements in our laboratory, using the 2% DOPC-dodecane lipid. With very lipophilic molecules, glycocholic acid added to the donor solution slightly reduced permeabilities, taurocholic acid increased permeabilities, but SLS arrested membrane transport altogether in several cases (especially cationic, surface-active drugs such as CPZ). 

Bile salt export pump (BSEP gene symbol ABCB11) mediates the biliary excretion of nonconjugated bile salts, such as taurocholic acid, glycocholic acid and cholic acid, and therefore is responsible for the formation of the bile acid-dependent bile flow [97, 98]. Its hereditary defect results in the acquisition of PFIC2, a potentially lethal disease which requires liver transplantation [17, 81, 82, 99]. As discussed in Section 12.5.2, the inhibition of BSEP following drug administration may result in cholestasis. 

Glycocholic Acid.—Fresh ox bile (2-0-2 5 1.) is obtained from a... 

Occasionally the glycocholic acid does not crystallise from the acidified bile until several days have elapsed. Frequent shaking has an accelerating effect. With summer bile the experiment often fails because the components of such bile crystallise with more difficulty. As far as experience goes, this has never been the case in winter. 

Before leaving the liver, a large proportion of the bile acids are activated with CoA and then conjugated with the amino acids g/ycine or taurine (2 cf A). In this way, cholic acid gives rise to glycocholic acid and taurocholic acid. The liver bile secreted by the liver becomes denser in the gallbladder as a result of the removal of water (bladder bile 3). 

Fig. 3 Electrophoretic ionic mobilities fj, of propranolol as influenced by BS concentration buffer x mM BS, 20 mM phosphate, pH = 7.4, detection 220 nm m— electrophoretic ionic mobility /r, GC—glycocholic acid, GDC—glycodeoxycholic acid, GCDC—glycochenodeoxycholic acid.

Table 5.4.6 Serum BA composition in healthy subjects (1,2), in a patient (3) with primary biliary cirrhosis (PBC) before (A) and after (B) treatment with ampicillin and in a patient (4) with PBC before (A) and after (B) treatment with UDCA. Results are expressed in nmol/ml. RDS% of three measurements was in the range 3.1-7.5%. - Means -detectable value (adapted from [20]). GCA glycocholic acid, GDCA glycodeoxycholic acid, GCDCA glycochenodeoxycholic acid, GLCA glycolithocholic acid,...

Glycollthocholic acid (GLCA) Glycodeoxycholic acid (GDCA) Glycocholic acid (GCA)... 

The structures of the salts of glycocholic acid and taurocholic acid are ... 

Detection of 2 paired bile acids by A. Strecker the taurin-containing cholic acid and the glycine-containing cholic acid, respectively designated tauro-cholic and glycocholic acid by C.G Lehmann in 1854. 

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