Archive image from page 505 of Currents in biochemical research, 1956;. Currents in biochemical research, 1956; twenty-seven essays charting the present course of biochemical research and considering the intimate relationship of biochemistry to medicine, physiology, and biology currentsinbioche1956gree Year: 1956 ( KONRAD BLOCK ring closure need not be preceded by oxidation. Of some in- terest in this connection is the structure of ambrein (Figure 5), a terpene alcohol which is a pathological excretion product of the sperm whale, and undoubtedly originates from squalene by partial cyclization
Archive image from page 505 of Currents in biochemical research, 1956;. Currents in biochemical research, 1956; twenty-seven essays charting the present course of biochemical research and considering the intimate relationship of biochemistry to medicine, physiology, and biology currentsinbioche1956gree Year: 1956 ( KONRAD BLOCK ring closure need not be preceded by oxidation. Of some in- terest in this connection is the structure of ambrein (Figure 5), a terpene alcohol which is a pathological excretion product of the sperm whale, and undoubtedly originates from squalene by partial cyclization. The linkage of the hydroxyl group of this interesting compound to the carbon corresponding to Cg of the steroids may be taken as evidence that oxidation occurred after rings A and B had been established. In view of the obscure circumstances which attend the origin of this alcohol, it would be AMBREIN TETRACYCLOSQUALENE Fig. 5. Transformations ot squalene. hazardous to say that ambrein, though it is derived from a bio- logical source, is actually the product of an enzymatic action. In any event, it is questionable that much can be deduced from the structure of either tetracyclosqualene or ambrein regarding the stage at which the oxidation step occurs in steroid biogenesis. It must also be borne in mind that in the chemical cyclization the reagent attacks the symmetrical squalene chain at two equivalent points. One would suspect, on the other hand, that in the analogous biological reaction one of the two sensitive double bonds must be shielded so that the aliphatic portion which becomes the isooctyl side chain of the sterol can be pre- served. Conceivably, the squalene molecule is rendered asym- 484
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