NAD(P)+ transhydrogenase (Si-specific)
NAD(P)+ transhydrogenase (Si-specific) | |||||||||
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Identifiers | |||||||||
EC number | 1.6.1.1 | ||||||||
CAS number | Template:CAS | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / EGO | ||||||||
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In biochemistry, NAD(P)+ transhydrogenase (Si-specific) (EC 1.6.1.1) is an enzyme that catalyzes the chemical reaction
- NADPH + NAD+ NADP+ + NADH
Thus, the two substrates of this enzyme are NADPH and NAD+, whereas its two products are NADP+ and NADH. This enzyme participates in nicotinate and nicotinamide metabolism. It employs one cofactor, FAD.
Physiological function
Si-specific transhydrogenase is a soluble protein found in some Gammaproteobacteria and gram-positive bacteria. Enterobacteriaceae are known to possess both a soluble and a membrane-bound transhydrogenase.[1] In living cells this enzyme primarily operates in the direction consuming NADPH and producing NADH, as the physiological ratio of NADPH/NADP+ is much higher than the ratio of NADH/NAD+.[1] Its chief function in vivo is the reoxidization of excess NADPH.[2]
Nomenclature
This enzyme belongs to the family of oxidoreductases, specifically those acting on NADH or NADPH with NAD+ or NADP+ as acceptor. The systematic name of this enzyme is NADPH:NAD+ oxidoreductase (Si-specific). Other names in common use include non-energy-linked transhydrogenase, NAD(P)+ transhydrogenase (B-specific), and soluble transhydrogenase.
Older literature often uses ambiguous names such as pyridine nucleotide transhydrogenase, transhydrogenase, NAD(P)+ transhydrogenase, nicotinamide nucleotide transhydrogenase, NADPH-NAD+ transhydrogenase, pyridine nucleotide transferase, or NADPH-NAD+ oxidoreductase, which can equally apply to the more common NAD(P)+ transhydrogenase (Re/Si-specific).
References
Further reading
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