76 



ROLAND FISCHER 



a low and sometimes reversible affinity, while covalent bonds bind the com- 

 pound more firmly to protein (which means high affinity or sorption values). 

 Of course, binding to wool occurs when factors affecting solubility, permeability 

 and attraction of the compound are already operative. 



In the last few years new data have been contributed to the discussion of the 

 a-helix configuration of polypeptide chains from proteins of the a-keratin types. 

 The suggestion of seven-strand protein cables in parallel orientation offered by 

 Pauling and Corey (1953) resolves the difficulties involved in the previously 

 surmised simple structure of the a-keratin protein. A repeating unit of seven 

 amino acid residues is believed to give rise to a seven-strand a-cable about 30 A 

 in diameter. The x-ray pattern of hair and other a-keratin proteins can be ac- 

 counted for by such a unit. 



VII 

 Coda 



For Serotonin the affinity value is low = 0.9 mMoles X 10" 2 gm. wool. This 

 is in agreement with the results of Boyd, Rothlin, et al., (1955), who found LSD 

 to be a potent antagonist of Serotonin when tested on the isolated uterus of 

 castrated or estrogen pre-treated rats. Serotonin is also an inhibitor of both 

 types of cholinesterase (Langemann, 1954). 



Let us recall in this context that the affinity value of LSD is three times higher 

 than that of Serotonin. 



HO 



^ 



-C— CH 2 — CH 2 NH 2 



V\ 



CH 



/ 



NH 



Serotonin 



HO 



CH 3 i 



-C— CHo— CH, • N 

 II \ 



ch r \ CH 3 ) 



/ ,' v <' 



NH / 



\ 

 v """Bufotenme 



The affinity of Bufotenine, on the other hand, was found to be higher than 

 that of LSD,i. e. 4 mMoles X 10" 2 gm. wool. This is indicative that Bufoten- 

 ine is a more potent adrenergic blocking agent than LSD 6 . 



6 Since affinity of a compound for wool does not reveal anything about the rate of 

 reaction of the compound, any prophecy referring to biological activity based on 

 affinity of a compound to wool is a very general one; among other things it does not 

 contain any information about the duration of that biological activity. 



