Skip to Content
Medical Term:


Pronunciation: kor'in

Definition: The cyclic system of four pyrrole rings forming corrinoids, which are the central structure of the vitamins B12 and related compounds, differing from porphin (porphyrin) in that two of the pyrrole rings are directly linked (C-19 to C-1).

[fr. core (of vitamin B12 molecule)]

© Copyright 2016 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.