Biochemical and Functional Characterization of RecombinantRhodnius prolixusPlatelet Aggregation Inhibitor 1 as a Novel Lipocalin with High Affinity for Adenosine Diphosphate and Other Adenine Nucleotides

Biochemistry ◽  
2002 ◽  
Vol 41 (11) ◽  
pp. 3810-3818 ◽  
Author(s):  
Ivo M. B. Francischetti ◽  
John F. Andersen ◽  
José M. C. Ribeiro
Keyword(s):  
Adenine Nucleotides ◽  
Functional Characterization ◽  
Adenosine Diphosphate ◽  
High Affinity ◽  
Aggregation Inhibitor

scholarly journals Functional Characterization of a High-Affinity Choline Transport System in Human Keratinocytes

2002 ◽  
Vol 119 (1) ◽  
pp. 118-121 ◽  
Author(s):  
Kathrin Hoffmann ◽  
Franziska Grafe ◽  
Wolfgang Wohlrab ◽  
Reinhard H. Neubert ◽  
Matthias Brandsch
Keyword(s):  
Transport System ◽  
Functional Characterization ◽  
Human Keratinocytes ◽  
Choline Transport ◽  
High Affinity

scholarly journals Functional characterization of two human sulphotransferase cDNAs that encode monoamine- and phenol-sulphating forms of phenol sulphotransferase: substrate kinetics, thermal-stability and inhibitor-sensitivity studies

1994 ◽  
Vol 302 (2) ◽  
pp. 497-502 ◽  
Author(s):  
M E Veronese ◽  
W Burgess ◽  
X Zhu ◽  
M E McManus
Keyword(s):  
Thermal Stability ◽  
Human Liver ◽  
Functional Characterization ◽  
Stability Studies ◽  
Functional Relationships ◽  
High Affinity ◽  
Electrophoretic Mobilities ◽  
Sensitivity Studies ◽  
Substrate Kinetics

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.

Functional characterization of high-affinity Na+/dicarboxylate cotransporter found in Xenopus laevis kidney and heart

2005 ◽  
Vol 289 (5) ◽  
pp. C1159-C1168 ◽  
Author(s):  
Naomi Oshiro ◽  
Ana M. Pajor
Keyword(s):  
Xenopus Laevis ◽  
Cdna Sequence ◽  
Citric Acid Cycle ◽  
Functional Characterization ◽  
Activation Kinetics ◽  
Electrophysiological Properties ◽  
High Affinity ◽  
The Family ◽  
Kidney Liver

The SLC13 gene family includes sodium-coupled transporters for citric acid cycle intermediates and sulfate. The present study describes the sequence and functional characterization of a SLC13 family member from Xenopus laevis, the high-affinity Na+/dicarboxylate cotransporter xNaDC-3. The cDNA sequence of xNaDC-3 codes for a protein of 602 amino acids that is ∼70% identical to the sequences of mammalian NaDC-3 orthologs. The message for xNaDC-3 is found in the kidney, liver, intestine, and heart. The xNaDC-3 has a high affinity for substrate, including a Km for succinate of 4 μM, and it is inhibited by the NaDC-3 test substrates 2,3-dimethylsuccinate and adipate. The transport of succinate by xNaDC-3 is dependent on sodium, with sigmoidal activation kinetics, and lithium can partially substitute for sodium. As with other members of the family, xNaDC-3 is electrogenic and exhibits inward substrate-dependent currents in the presence of sodium. However, other electrophysiological properties of xNaDC-3 are unique and involve large leak currents, possibly mediated by anions, that are activated by binding of sodium or lithium to a single site.

scholarly journals Functional characterization of the ferroxidase, permease high-affinity iron transport complex from Candida albicans

2011 ◽  
Vol 81 (2) ◽  
pp. 473-485 ◽  
Author(s):  
Lynn Ziegler ◽  
Alaina Terzulli ◽  
Ruchi Gaur ◽  
Ryan McCarthy ◽  
Daniel J. Kosman
Keyword(s):  
Candida Albicans ◽  
Iron Transport ◽  
Functional Characterization ◽  
High Affinity ◽  
Transport Complex
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