TY - JOUR
T1 - Isoelectric and mass characterization of human platelet thromboxane A2/prostaglandin H2 receptors
AU - Dorn, Gerald W.
PY - 1989/8/30
Y1 - 1989/8/30
N2 - To further characterize the human thromboxane A2 (TXA2)/prostaglandin H2 (PGH2) receptor, preparative isoelectric focusing (IEF) was performed on solubilized platelet membranes. TXA2/PGH2 receptors, assayed by specific binding of the TXA2/PGH2 antagonist [125I]PTA-OH, were electrofocused at pH 5.6. Scatchard analysis of IEF fraction pH 5.6 revealed a 180-fold concentration of TXA2/PGH2 receptors (Bmax=3650±228 pM/mg focused, 19±4 pM/mg unfocused) with no change in binding affinity (Kd=47±7 nM focused, 36±14 nM unfocused). SDS-polyacrylamide gel electrophoresis of photoaffinity-labelled electrofocused receptors revealed concentration of specifically labelled proteins having molecular masses of 49,000 and 27,000 Daltons. These results suggest that the human platelet TXA2/PGH2 receptor has a pI of 5.6, molecular mass of 49,000 Daltons, and may exist as a dimer. Preparative IEF should prove useful in the eventual purification of this receptor.
AB - To further characterize the human thromboxane A2 (TXA2)/prostaglandin H2 (PGH2) receptor, preparative isoelectric focusing (IEF) was performed on solubilized platelet membranes. TXA2/PGH2 receptors, assayed by specific binding of the TXA2/PGH2 antagonist [125I]PTA-OH, were electrofocused at pH 5.6. Scatchard analysis of IEF fraction pH 5.6 revealed a 180-fold concentration of TXA2/PGH2 receptors (Bmax=3650±228 pM/mg focused, 19±4 pM/mg unfocused) with no change in binding affinity (Kd=47±7 nM focused, 36±14 nM unfocused). SDS-polyacrylamide gel electrophoresis of photoaffinity-labelled electrofocused receptors revealed concentration of specifically labelled proteins having molecular masses of 49,000 and 27,000 Daltons. These results suggest that the human platelet TXA2/PGH2 receptor has a pI of 5.6, molecular mass of 49,000 Daltons, and may exist as a dimer. Preparative IEF should prove useful in the eventual purification of this receptor.
UR - http://www.scopus.com/inward/record.url?scp=0024419118&partnerID=8YFLogxK
U2 - 10.1016/0006-291X(89)92118-9
DO - 10.1016/0006-291X(89)92118-9
M3 - Article
C2 - 2528348
AN - SCOPUS:0024419118
SN - 0006-291X
VL - 163
SP - 183
EP - 188
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -