Cobalamin's (Vitamin B12) Surprising Function as a Photoreceptor
Related Experiment Video
Updated: Mar 20, 2026

Preparation of Living Isolated Vertebrate Photoreceptor Cells for Fluorescence Imaging
Published on: June 22, 2011
Zhuo Cheng1, Haruki Yamamoto1, Carl E Bauer1
1Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA.
Abstract:
Cobalamin (Vitamin B12) is an adenosyl- or methyl-donating cofactor for many enzymes, yet many proteins with unknown or nonenzymatic function also contain B12-binding domains. Recent studies show that light excitation energy can promote covalent linkage of B12 to transcription factors with this linkage, affecting gene expression. Thus, B12 now has a newly described regulatory function. Here, our bioinformatics analysis reveals other transcription factors, photoreceptors, kinases, and oxygen sensors that harbor a B12-binding domain that could also regulate activity in response to light absorption.
Related Concept Videos
Photoreceptors and Visual Pathways
Anatomy of the Eyeball
Channel Rhodopsins
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Photoreceptors and Plant Responses to Light
The Retina
The Photochemical Reaction Center

