B12 ja rikkiaineenvaihdunnan molekyylien osuutta metyyliryhmän siirrossa

 https://pubmed.ncbi.nlm.nih.gov/28379205/

 

Possible Involvement of Hydrosulfide in B₁₂-Dependent Methyl Group Transfer

John I Toohey  ¹

Affiliations

• PMID: 28379205
• PMCID: PMC6154648
• DOI: 10.3390/molecules22040582

Free PMC article

Abstract

Evidence from several fields of investigation lead to the hypothesis that the sulfur atom is involved in vitamin B₁₂-dependent methyl group transfer. To compile the evidence, it is necessary to briefly review the following fields: methylation, the new field of sulfane sulfur/hydrogen sulfide (S°/H₂S), hydrosulfide derivatives of cobalamins, autoxidation of hydrosulfide radical, radical S-adenosylmethionine methyl transfer (RSMT), and methionine synthase (MS). Then, new reaction mechanisms for B₁₂-dependent methyl group transfer are proposed; the mechanisms are facile and overcome difficulties that existed in previously-accepted mechanisms. Finally, the theory is applied to the effect of S°/H₂S in nerve tissue involving the "hypomethylation theory" that was proposed 50 years ago to explain the neuropathology resulting from deficiency of vitamin B₁₂ or folic acid. The conclusions are consistent with emerging evidence that sulfane sulfur/hydrogen sulfide may be beneficial in treating Alzheimer's disease.

Keywords: Alzheimer’s disease; cobalamin; dementia; hydrogen sulfide; hypomethylation; methionine auxotrophy; methionine synthase; methylation; radical S-adenosylmethionine methyl transferases; sulfane sulfur; viscose dialysis tubing.

 Conflict of interest statement

The author declares no conflict of interest.