THE VITAMIN A OF A EUPHAUSIID CRUSTACEAN

• Published in: Journal of General Physiology
• Main Authors: Wald, George, Brown, Paul K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Rockefeller University Press 1957
• Subjects: Meganyctiphanes norvegica
• Online Access: http://dx.doi.org/10.1085/jgp.40.4.627; https://rupress.org/jgp/article-pdf/40/4/627/1803135/627.pdf

The vitamin A of the euphausiid crustacean, Meganyctiphanes norvegica, consists almost wholly of the hindered cis isomer, neo-b (11-cis). In this animal vitamin A is concentrated almost entirely in the eyes; and its properties so closely resemble those of pure neo-b vitamin A as not in themselves to indicate that any other isomer is present. However, Fisher et al. (1955 b) have isolated a small fraction from this material which may be neo-c vitamin A (11, 13-dicis). The neo-b isomer was identified by its absolute absorption spectrum, the changes of absorption spectrum on isomerization, oxidation to neo-b retinene, and synthesis from the latter of rhodopsin. This identification is also in good accord with new, revised bioassays of Meganyctiphanes vitamin A by Plack et al. (1956).