The role of ascorbate in protein folding

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Ascorbate (Vitamin C) has a long-established role as a cofactor in collagen synthesis.
• Its involvement in protein folding extends beyond hydroxylation, particularly in disulfide bond formation.

Purpose of the Study:

• To elucidate the multifaceted roles of ascorbate in protein folding.
• To investigate the connection between ascorbate, hydroxylation, and oxidative protein folding in the endoplasmic reticulum.

Main Methods:

• Review of existing literature on ascorbate's enzymatic functions.
• Analysis of recent findings in genetically modified mice with compromised thiol oxidase and peroxiredoxin 4.

Main Results:

• Ascorbate is essential for prolyl 4-hydroxylase activity, preventing iron oxidation and enzyme inactivation.
• Dehydroascorbate, an oxidized form of ascorbate, participates in disulfide bond formation for secretory proteins.
• Recent studies in mice suggest a critical role for ascorbate in oxidative protein folding via endoplasmic reticulum thiol oxidase and peroxiredoxin 4.

Conclusions:

• Ascorbate plays a dual role in protein folding: facilitating hydroxylation and enabling disulfide bond formation.
• Impaired ascorbate levels are linked to compromised oxidative protein folding, suggesting a broader impact on protein homeostasis.
• This research highlights a novel connection between ascorbate's functions in hydroxylation and oxidative protein folding.