Cholanoic acids

DIHYDROXYCHOEANIC ACID see DAQ400 3-a,12-a-DIHYDROXYCHOLANIC ACID see DAQ400 3-a,12-a-DIHYDROXY-5-P-CHOLANOIC ACID see DAQ400... 

In a separate study, Branden (11) modelled the active site+ substrate interactions of ADH and several 36-and 3a-hydroxy steroids, based on the kinetic work of others (4,5). He showed that 3S-hydroxy-53-cholanoic acid fits in the active site rather... 

Figure 3. Stereoview of the model of (330H-5/3 cholanoic acid in orientations similar to those in Figures 1, 2, 4. The steroid extends back into the yawning entrance cavity of the enzyme.

Figure 4. Stereoview of a model of a30H-5fi cholanoic acid. Placing the a30H oxygen atom in bonding position causes the rest of the steroid to be shifted in the entrance cavity such that serious overlap near the D ring of the steroid cannot be...

Hydride reduction of 3-oxo-A-nor-5jff-cholanoic acid afforded a preponderance of the 3a-hydroxy-compound, although the ratio of 3a 3) alcohols is less than with the normal six-membered homologues. Lithium-ammonia reduction afforded equal amounts of 3a- and 3)5-epimers. AB-Dinor-cholestenone and -testosterone have been prepared by the following sequence ... 

The specificity of the enzymes involved in the conversion of 3a,7a,12a-trihy-droxy-5j8-cholestanoic acid into cholic acid is not known. It is probable that the same or a similar system is involved in the conversion of 3a,7a-dihydroxy-5)8-cholanoic acid into chenodeoxycholic acid. Cass et al. showed that there was a competitive inhibition of side-chain oxidation of 3a,7a-dihydroxy-5 -cholestanoic acid by 3a,7a,12a-trihydroxy-5)8-cholestanoic acid in vivo in hamsters [152]. 

Surface studies of insoluble monolayers of all the common unconjugated bile acids, including the unsubstituted cholanoic acid, have been carried out by a number of workers and thoroughly reviewed [5]. Being insoluble non-swelling amphiphiles with limited aqueous solubility, their surface pressure-area (v-A) isotherms can be measured satisfactorily with a Langmuir-Pockels surface balance on an aqueous subphase containing 3-6 M NaCl to salt out polar functions and at sufficient acidic pH (1-3) to prevent ionization [5,6). 

Cholanoic acid 2 3 50 42 N.O. 20 Liquid Isotherm similar to cholesterol... 

Fig. 11. Effects of temperature on water solubility (in negative logarithmic units, moles/l) of undissociated free bile acids at pH 3. (Modified from ref. 90.) Numbers and Greek letters denote position and orientation, respectively, of hydroxyl groups in each 5/3-cholanoic acid. Mean m.p.s [34-41, and private communications from A. Roda and A.F. Hofmann] are indicated on each curve.

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