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. 1974 Apr;71(4):1351–1355. doi: 10.1073/pnas.71.4.1351

An Intermediate Complex in the Dissociation of Aspartate Transcarbamylase

David R Evans 1, Styliani C Pastra-Landis 1, William N Lipscomb 1
PMCID: PMC388226  PMID: 4598300

Abstract

The multisubunit enzyme aspartate transcarbamylase consists of six copies of two types of polypeptide chains, catalytic (C) and regulatory (R). A complex formed by the partial dissociation of this enzyme has been isolated. This species, which has the structure C6R4, is a likely intermediate in the stepwise dissociation of aspartate transcarbamylase induced by mercurials. The formation of the complex is the result of the release of a single regulatory dimer (R2) from the parent molecule.

The specific activity of the intermediate is essentially the same as that of aspartate transcarbamylase. By contrast, both homotropic and heterotropic interactions are reduced, but not abolished. These observations suggest that the allosteric transitions involved in the control mechanisms do not require the intact structure C6R6.

Keywords: thiols, mercurials, dissociation, central cavity, intermediate

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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