TY - JOUR
T1 - Identification and Characterization of TRP14, a Thioredoxin-related Protein of 14 kDa
T2 - New insights into the specificity of thioredoxin function
AU - Jeong, Woojin
AU - Yoon, Hae Won
AU - Lee, Seung Rock
AU - Rhee, Sue Goo
PY - 2004/1/30
Y1 - 2004/1/30
N2 - We have identified and characterized a 14-kDa human thioredoxin (Trx)-related protein designated TRP14. This cytosolic protein was expressed in all tissues and cell types examined, generally in smaller amounts than Trx1. Although TRP14 contains five cysteines, only the two Cys residues in its WCPDC motif were exposed and redox sensitive. Unlike Trx1, which was an equally good substrate for both Trx reductase 1 (TrxR1) and TrxR2, oxidized TRP14 was reduced by TrxR1 but not by TrxR2. Biochemical characterization of TRP14 suggested that, like Trx1, TRP14 is a disulfide reductase; its active site cysteine is sufficiently nucleophilic with the pKa value of 6.1; and its redox potential (-257 mV) is similar to those of other cellular thiol reductants. However, although TRP14 reduced small disulfide-containing peptides, it did not reduce the disulfides of known Trx1 substrates, ribonucleotide reductase, peroxiredoxin, and methionine sulfoxide reductase. These results suggest that TRP14 and Trx1 might act on distinct substrate proteins.
AB - We have identified and characterized a 14-kDa human thioredoxin (Trx)-related protein designated TRP14. This cytosolic protein was expressed in all tissues and cell types examined, generally in smaller amounts than Trx1. Although TRP14 contains five cysteines, only the two Cys residues in its WCPDC motif were exposed and redox sensitive. Unlike Trx1, which was an equally good substrate for both Trx reductase 1 (TrxR1) and TrxR2, oxidized TRP14 was reduced by TrxR1 but not by TrxR2. Biochemical characterization of TRP14 suggested that, like Trx1, TRP14 is a disulfide reductase; its active site cysteine is sufficiently nucleophilic with the pKa value of 6.1; and its redox potential (-257 mV) is similar to those of other cellular thiol reductants. However, although TRP14 reduced small disulfide-containing peptides, it did not reduce the disulfides of known Trx1 substrates, ribonucleotide reductase, peroxiredoxin, and methionine sulfoxide reductase. These results suggest that TRP14 and Trx1 might act on distinct substrate proteins.
UR - http://www.scopus.com/inward/record.url?scp=0942298136&partnerID=8YFLogxK
U2 - 10.1074/jbc.M307932200
DO - 10.1074/jbc.M307932200
M3 - Article
C2 - 14607844
AN - SCOPUS:0942298136
SN - 0021-9258
VL - 279
SP - 3142
EP - 3150
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 5
ER -