| Autor: |
Seo HS; Division of Applied Life Sciences, Graduate School of Gyeongsang National University, Jinju 660-701, Korea., Jeong JY, Nahm MY, Kim SW, Lee SY, Bahk JD |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of biochemistry and molecular biology [J Biochem Mol Biol] 2003 Mar 31; Vol. 36 (2), pp. 196-200. |
| DOI: |
10.5483/bmbrep.2003.36.2.196 |
| Abstrakt: |
Previously, we reported the biochemical properties of RGA1 that is expressed in Escherichia coli (Seo et al., 1997). The activities of RGA1 that hydrolyzes and binds guanine nucleotide were dependent on the MgCl(2) concentration. The steady state rate constant (k(cat) ) for GTP hydrolysis of RGA1 at 2 mM MgCl(2) was 0.0075 +/- 0.0001 min(-1). Here, we examined the effects of pH and cations on the GTPase activity. The optimum pH at 2 mM MgCl(2) was approximately 6.0; whereas, the pH at 2 mM NH(4)Cl was approximately 4.0. The result from the cation dependence on the GTPase (guanosine 5'-triphosphatase) activity of RGA1 under the same condition showed that the GTP hydrolysis rate (k(cat)= 0.0353 min(-1)) under the condition of 2 mM NH(4)Cl at pH 4.0 was the highest. It corresponded to about 3.24-fold of the k(cat) value of 0.0109 min(-1) in the presence of 2 mM MgCl(2) at pH 6.0. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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