Primary structure and functional characterization of a high-affinity glutamate transporter

Nature ◽  
1992 ◽  
Vol 360 (6403) ◽  
pp. 467-471 ◽  
Author(s):  
Yoshikatsu Kanai ◽  
Matthias A. Hediger
1986 ◽  
Vol 261 (3) ◽  
pp. 1177-1182 ◽  
Author(s):  
F G Oppenheim ◽  
Y C Yang ◽  
R D Diamond ◽  
D Hyslop ◽  
G D Offner ◽  
...  

2002 ◽  
Vol 119 (1) ◽  
pp. 118-121 ◽  
Author(s):  
Kathrin Hoffmann ◽  
Franziska Grafe ◽  
Wolfgang Wohlrab ◽  
Reinhard H. Neubert ◽  
Matthias Brandsch

1994 ◽  
Vol 302 (2) ◽  
pp. 497-502 ◽  
Author(s):  
M E Veronese ◽  
W Burgess ◽  
X Zhu ◽  
M E McManus

The present paper describes the functional characterization of two human aryl sulphotransferase (HAST) cDNAs, HAST1 and HAST3, previously isolated by us from liver and brain, respectively [Zhu, Veronese, Sansom, and McManus (1993) Biochem. Biophys. Res. Commun. 192, 671-676; Zhu, Veronese, Bernard, Sansom and McManus (1993) Biochem. Biophys. Res. Commun. 195, 120-127]. These appear to encode the two major forms of phenol sulphotransferase (PST) characterized in a number of human tissue cytosols, these being the phenolsulphating (P-PST) and monoamine-sulphating (M-PST) forms of phenol sulphotransferase. HAST1 and HAST3 cDNAs were functionally expressed in COS-7 cells and kinetically characterized using the model substrates for P-PST and M-PST, p-nitrophenol and dopamine (3,4-dihydroxyphenethylamine) respectively. COS-expressed HAST1 was shown to be enzymatically active in sulphating p-nitrophenol with high affinity (Km 0.6 microM), whereas dopamine was the preferred substrate for HAST3 (Km 9.7 microM). HAST1 could also sulphate dopamine, as could HAST3 sulphate p-nitrophenol, but the Km for these reactions were at least two orders of magnitude greater than for the preferred substrates. COS-expressed HAST1 and HAST3 displayed inhibition profiles with the ST inhibitor 2,6-dichloro-4-nitrophenol (DCNP), identical with human liver cytosolic P-PST and M-PST activities respectively. Thermal-stability studies with the expressed enzymes showed that HAST1 was considerably more thermostable (TS) than HAST3, which is consistent with P-PST being termed the TS PST and M-PST being termed the thermolabile (TL) PST. Western immunoblot analyses of the expressed PST proteins using an antibody generated to a bacterially expressed rat liver aryl/phenol ST showed that HAST1 and HAST3 migrated as single proteins with different electrophoretic mobilities (32 versus 34 kDa). This is consistent with the differences in electrophoretic mobilities observed for P-PST and M-PST in a variety of tissues reported by other workers. This report on the functional characterization of P-PST and M-PST cDNAs provides important information on the structural as well as functional relationships of human PSTs, which sulphate a vast array of exogenous and endogenous compounds.


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