The presence of a methyl group, along with the naphthoquinone structure, is essential for the biological activity of vitamin K, particularly its role in blood clotting and bone metabolism.

The "Sulfur Insulin Deformation Hypothesis" suggests that organic sulfur deficiency can lead to insulin deformation and impaired function in Type 2 Diabetes (T2D), rather than solely relying on the traditional concept of insulin resistance. This hypothesis proposes that proper disulfide bond formation within the insulin molecule is crucial for its functionality, and that a lack of organic sulfur can disrupt this process. 

Insulin is a protein hormone composed of two chains linked by disulfide bonds, which are formed by sulfur atoms. These bonds are essential for maintaining the proper three-dimensional structure of insulin, which is crucial for its activity. 

Niacin's Role:
Long-term niacin treatment has been shown to cause whole-body insulin resistance. 

Adipose Tissue 
Adipocyte
MicroRNAs
Lipolysis
PDE3B

Homocysteine
Methyl CH3


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Unraveling the Sulfur Insulin Deformation Hypothesis: A Novel Therapeutic Avenue for Type 2 Diabetes

https://www.qeios.com/read/UK9O6V

Niacin

https://examine.com/supplements/vitamin-b3/research/?srsltid=AfmBOorOjULBJ4uD0Tdoqh4FbsitOEFGlOVwh2e7MSqiZ6XpPwv3wnoe#PlOn4Jq-interactions-with-glucose-metabolism