Plant thioredoxin h: an animal-like thioredoxin occurring in multiple cell compartments.
Thioredoxin h has been purified to electrophoretic homogeneity from spinach roots using a procedure devised for leaves. The root thioredoxin (h2 form) differed from chloroplast and animal thioredoxins in showing an atypical active site (Cys-Ala-Pro-Cys) but otherwise resembled animal thioredoxin in structure. Sequence data for a total of 72 residues of spinach root thioredoxin h2 (about 69% of the primary structure) showed 43-44% identity with rabbit and rat thioredoxin. Analysis of cell fractions from the endosperm of germinating castor beans revealed that thioredoxin h occurs in the cytosol, endoplasmic reticulum, and mitochondria. The present findings demonstrate a similarity between plant thioredoxin h and animal thioredoxins in structure and intracellular location and raise the question of whether these proteins have similar functions.
Marcus
F
F
Chiron Research Laboratories, Chiron Corporation, Emeryville, California 94608.
Chamberlain
S H
SH
Chu
C
C
Masiarz
F R
FR
Shin
S
S
Yee
B C
BC
Buchanan
B B
BB
D000595:Amino Acid Sequence; D001665:Binding Sites; D002451:Cell Compartmentation; D002851:Chromatography, High Pressure Liquid; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000032:analysis*; D010944:Plants; D012689:Sequence Homology, Nucleic Acid; D054480:Thioredoxin h; D014357:Trypsin
D010940:Plant Proteins; D054480:Thioredoxin h; D014357:Trypsin