A new member of alpha 1-adrenoceptor-coupled G alpha h (transglutaminase II) family in pig heart: purification and characterization
Experimental & Molecular Medicine
;
: 81-86, 1998.
Article
in English
| WPRIM
| ID: wpr-70155
ABSTRACT
We previously reported an identification of a 77-kDa GTP-binding protein that co-purified with the alpha 1-adrenoceptor following ternary complex formation. In the present paper, we report on the purification and characterization of this GTP-binding protein (termed G alpha h5) isolated from pig heart membranes. After solubilization of pig heart membranes with NaCl, G alpha h5 was purified by sequential chromatographies using DEAE-Cellulose, Q-Sepharose, and GTP-agarose columns. The protein displayed high-affinity GTP gamma S binding which is Mg(2+)-dependent and saturable. The relative order of affinity of nucleotide binding by G alpha h5 was GTP > GDP > ITP >> ATP > or = adenyl-5'-yl imidodiphosphate, which was similar to that observed for other heterotrimeric G-proteins involved in receptor signaling. Moreover, the G alpha h5 demonstrated transglutaminase (TGase) activity that was blocked either by EGTA or GTP gamma S. In support of these observations, the G alpha h5 was recognized by a specific antibody to G alpha h7 or TGase II, indicating a homology with G alpha h (TGase II) family. These results demonstrate that 77-kDa G alpha h5 from pig heart is an alpha 1-adrenoceptor-coupled G alpha h (TGase II) family which has species-specificity in molecular mass.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Swine
/
Binding, Competitive
/
Binding Sites
/
Transglutaminases
/
Guanosine 5'-O-(3-Thiotriphosphate)
/
Receptors, Adrenergic, alpha-1
/
GTP-Binding Proteins
/
Cross Reactions
/
Animals
/
Molecular Weight
Language:
English
Journal:
Experimental & Molecular Medicine
Year:
1998
Type:
Article
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