SDHD

SDHD (Succinate Dehydrogenase Complex Subunit D) is a protein that in humans is encoded by the SDHD gene. It is located on the chromosome 11 at position q23. SDHD is a small (15 kDa) mitochondrial membrane protein that is a part of the Succinate dehydrogenase (SDH) complex (also known as complex II) of the mitochondrial respiratory chain.

Function

The SDHD gene is a subunit of the Succinate dehydrogenase complex, a key enzyme complex of the tricarboxylic acid cycle (TCA cycle), which is also part of the mitochondrial respiratory chain. This complex is responsible for the oxidation of succinate, coupling the reaction to the reduction of ubiquinone to ubiquinol. This reaction is a step in the Krebs cycle, which is involved in the metabolism of glucose and oxygen to produce energy in the form of ATP.

Clinical significance

Mutations in the SDHD gene are associated with hereditary paraganglioma and pheochromocytoma, rare tumors that usually occur in the head, neck, and upper body. These mutations are inherited in an autosomal dominant manner, but they require a second, non-inherited mutation to cause the tumor. This is known as the "second hit" hypothesis.

See also

• Succinate dehydrogenase
• Mitochondrial respiratory chain
• Hereditary paraganglioma
• Pheochromocytoma

References

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External links

• SDHD at the US National Library of Medicine Medical Subject Headings (MeSH)