The enzyme that catalyzes this reaction is called argininosuccinate synthetase.

Question

The enzyme that catalyzes this reaction is called argininosuccinate synthetase. The following image shows the three-dimensional structure of one of the subunits of the enzyme, which normally occurs as a tetramer.

                        Describe the major structural features of this protein (2 points).

The reaction catalyzes by argininosuccinate synthetase occurs in two steps, as shown in the following figure.

                        Describe what is happening in this reaction in your own words (4 points).

The aspartate used in this reaction arises by transamination with glutamate as the donor. Diagram what happens in this reaction (you do not have to draw the structures

Explanation / Answer

Describe the major structural features of this protein

Argininosuccinate synthetase is a homotetramer, with every subunit comprising of 412 buildups.

The interfaces between subunits contain various salt extensions and hydrogen bonds, and the C-end of every subunit is included in oligomerization by collaborating with the C-ends and nucleotide-restricting spaces of alternate subunits.

Argininosuccinate synthase or synthetase (ASS; EC 6.3.4.5) ; IT is a chemical that catalyzes the amalgamation of argininosuccinate from citrulline and aspartate.

ASS is in charge of the third step of the urea cycle and one of the responses of the citrulline-NO cycle.

The quality that encodes for this chemical, ASS, is situated on chromosome 9. In people, ASS is communicated for the most part in the cells of liver and kidney. The communicated ASS quality is no less than 65 kb long, including no less than 12 intron.

In the initial step of the catalyzed response, citrulline assaults the -phosphate of ATP to frame citrulline adenylate, a receptive halfway. The connection of AMP to the ureido (urea-like) gathering on citrulline actuates the carbonyl community for resulting nucleophilic assault. This initiation encourages the second step, in which the -amino gathering of aspartate assaults the ureido aggregate. Assault by aspartate is the rate-restricting stride of the response. This progression delivers free AMP and L-argininosuccinate.

Thermodynamically, adenylation of the citrulline ureido gathering is more positive than the undifferentiated from phosphorylation. Furthermore, assault by citrulline at the -phosphate of ATP creates a likeness pyrophosphate, which can be hydrolyzed in a thermodynamically positive response to give extra vitality to drive the adenylation.

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