Anthranilate synthetase, an enzyme specified by the tryptophan operon of Escherichia coli: Comparative studies on the complex and the subunits.
نویسندگان
چکیده
The properties of the anthranilate synthetase complex and its separated subunits were compared in catalyzing the anthranilate synthetase reaction, chorismate + l-glutamine or NH(4) (+) --> anthranilate, and the transferase reaction, anthranilate + 5'-phosphorylribosyl-1-pyrophosphate --> phosphoribosyl anthranilate. It is shown that anthranilate synthetase component I is activated by normal anthranilate synthetase component II, a component II(CRM) (CRM = immunologically cross-reacting material), and by a presumed fragment of component II produced by a deletion mutant. Significant differences between the complex and its subunits are demonstrated with respect to substrate affinity, thermostability, feedback inhibitor sensitivity, and activity in the presence of various divalent cations. Of particular interest are the findings that the transferase activity of component II is only inhibitable by l-tryptophan when the component is in the complex and that this inhibition does not appear to depend upon the feedback-sensitive site of component I.
منابع مشابه
Anthranilate synthetase, an enzyme specified by the tryptophan operon of Escherichia coli: purification and characterization of component I.
A procedure employed in the purification of anthranilate synthetase component I of Escherichia coli is described. The purified component appears homogeneous by starch gel electrophoresis and by sedimentation analysis. A molecular weight of 60,000 was estimated by gel filtration of Sephadex G-100. This value is consistent with the molecular weight estimated from the sedimentation and diffusion c...
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A procedure employed in the purification of anthranilate synthetase component I of Escherichia coli is described. The purified component appears homogeneous by starch gel electrophoresis and by sedimentation analysis. A molecular weight of 60,000 was estimated by gel filtration on Sephadex G-100. This value is consistent with the molecular weight estimated from the sedimentation and diffusion c...
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ورودعنوان ژورنال:
- Journal of bacteriology
دوره 97 2 شماره
صفحات -
تاریخ انتشار 1969