Reviewed, UniProtKB/Swiss-Prot Q9S926 (MDAR2_SOYBN)

Names and origin

Protein names	Recommended name:     Monodehydroascorbate reductase II       Short name=MDARII       Short name=MRII     EC=1.6.5.4 Alternative name(s):     Ascorbate free radical reductase II       Short name=AFR reductase II
Organism	Glycine max (Soybean)
Taxonomic identifier	3847 [NCBI]
Taxonomic lineage	Eukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › eurosids I › Fabales › Fabaceae › Papilionoideae › Phaseoleae › Glycine

Protein attributes

Sequence length	10 AA.
Sequence status	Fragment.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Catalyzes the conversion of monodehydroascorbate to ascorbate, oxidizing NADH in the process.
Catalytic activity	NADH + 2 monodehydroascorbate = NAD+ + 2 ascorbate. Ref.1
Cofactor	FAD. Ref.1
Sequence similarities	Belongs to the FAD-dependent oxidoreductase family.
biophysicochemical properties	Kinetic parameters: KM=5.6 µM for NADH KM=150 µM for NADPH KM=7 µM for monodehydroascorbate Vmax=288 µmol/min/mg enzyme for NADH oxidation reaction pH dependence: Optimum pH is 8.0-9.0.

Ontologies

Keywords
Domain	Redox-active center
Ligand	FAD Flavoprotein NAD
Molecular function	Oxidoreductase
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological process	oxidation reduction Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	monodehydroascorbate reductase (NADH) activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	‹1 – ›10	›10	Monodehydroascorbate reductase II		PRO_0000209144
Regions
	Nucleotide binding	5 – ›10	›6	FAD By similarity UniProtKB P42454
Experimental info
	Non-terminal residue	1	1
	Non-terminal residue	10	1

Sequences

	Sequence		Length	Mass (Da)
	Q9S926-1 [UniParc]. Last modified May 1, 2000. Version 1. Checksum: 848025504B5339D1	FASTA	10	1,153
	10 AKTFKYIILG

References

[1]

"Purification and characterization of monodehydroascorbate reductase from soybean root nodules." Dalton D.A., Langeberg L., Robbins M. Arch. Biochem. Biophys. 292:281-286(1992) [PubMed: 1727643] [Abstract] Cited for: PROTEIN SEQUENCE, CATALYTIC ACTIVITY, COFACTOR. Strain: cv. Williams. Tissue: Root nodule.

Cross-references

Sequence databases
PIR	A44871.
3D structure databases
ModBase	Search...
Enzyme and pathway databases
BRENDA	1.6.5.4. 299.
Family and domain databases
ProtoNet	Search...

Entry information

Entry name

MDAR2_SOYBN

Accession

Primary (citable) accession number: Q9S926

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 19, 2004
Last sequence update:	May 1, 2000
Last modified:	January 20, 2009
This is version 25 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

PPAP (Plant Proteome Annotation Project)