. Carotenoids, their comparative biochemistry. Carotenoids. ANIMAL CAROTENOIDS hatched naupHi are entirely pink. * ® This is consistent with the Hbera- tion by denaturation or some similar process of the carotenoid from its protein complex. Ball's ^ ^ work, however, raises another possibility, that the colour is still due to a chromoprotein but one in which the protein-carotenoid linkage has changed from a salt type (ovoverdin) to some other type, for he has succeeded in producing a reddish-pink chromoprotein from the blue material. A solution of the blue pigment in 25 per cent saturated ammo
. Carotenoids, their comparative biochemistry. Carotenoids. ANIMAL CAROTENOIDS hatched naupHi are entirely pink. * ® This is consistent with the Hbera- tion by denaturation or some similar process of the carotenoid from its protein complex. Ball's ^ ^ work, however, raises another possibility, that the colour is still due to a chromoprotein but one in which the protein-carotenoid linkage has changed from a salt type (ovoverdin) to some other type, for he has succeeded in producing a reddish-pink chromoprotein from the blue material. A solution of the blue pigment in 25 per cent saturated ammonium sulphate was slowly treated with N hydrochloric acid at 0° ; the colour gradually changed from blue to red ; addition of cold disodium hydrogen phosphate solution restored the original colour. If, however, the phosphate was not added but the acid solution brought directly to 50 per cent, saturation with ammonium sulphate the red pigment was precipitated ; it is soluble in water but cannot be reconverted into the blue pigment, the salt linkage having been irreversibly severed. When astaxanthin is treated vvith potassium butoxide in the absence of air it turns blue owing to the enolization of the hydroxyl groups foUow^ed by the formation of a potassium salt. 47. & 2,5 e Qn admitting air this salt is immediately oxidized to astacin, viz. : KO He Me Me ..JL, J v^^y\AAA/v\vw"' â "" o-/>vVv\aa, v_/... Me Me Me 0 The existence of the blue chromoprotein complex in lobster carapaces is explained in the same way, enolic astaxanthin is bound by ionic forces (salt link) to a protein and is in some way stabilized : ^ T^Me Me Me M Protein. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Goodwin, T. W. (Trevor Walworth). New York, Chemical Pub. Co.
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