Sandbox Reserved 685: Difference between revisions
No edit summary |
No edit summary |
||
| Line 22: | Line 22: | ||
results have proved that the mechanism for the formation of argininosuccinate consists of at least two distinct chemical steps with the formation of citrulline adenylate as a reactive intermediate. Argininosuccinate synthetase catalyzes the reversible conversion of citrulline, aspartate, and ATP to argininosuccinate, AMP, and inorganic pyrophosphate. Step 1, activated citrulline-adenylate is formed, releasing inorganic pyrophosphate. Step 2, nucleophilic attack by aspartate amino group forms argininosuccinate and releases AMP.<ref>http://www.jbc.org/content/277/15/13074.full#F1)</ref> | results have proved that the mechanism for the formation of argininosuccinate consists of at least two distinct chemical steps with the formation of citrulline adenylate as a reactive intermediate. Argininosuccinate synthetase catalyzes the reversible conversion of citrulline, aspartate, and ATP to argininosuccinate, AMP, and inorganic pyrophosphate. Step 1, activated citrulline-adenylate is formed, releasing inorganic pyrophosphate. Step 2, nucleophilic attack by aspartate amino group forms argininosuccinate and releases AMP.<ref>http://www.jbc.org/content/277/15/13074.full#F1)</ref> | ||
L-Argininosuccinate, L-histidine, and L-tryptophan inhibited the enzyme activity at saturating amounts of the substrates. L-Norvaline, L-argininosuccinate, L-arginine, L-isoleucine, and L-valine competitively inhibited the enzyme activity at a low concentration of L-citrulline. Argininosuccinate and L-arginine competitively inhibited the enzyme activity at a low concentration of L-aspartate.<ref>http://www.ncbi.nlm.nih.gov/pubmed/447618</ref>This study proved that a number of amino acids can inhibit the Argininosuccinate synthetase enzyme. | L-Argininosuccinate, L-histidine, and L-tryptophan inhibited the enzyme activity at saturating amounts of the substrates. L-Norvaline, L-argininosuccinate, L-arginine, L-isoleucine, and L-valine competitively inhibited the enzyme activity at a low concentration of L-citrulline. Argininosuccinate and L-arginine competitively inhibited the enzyme activity at a low concentration of L-aspartate.<ref>http://www.ncbi.nlm.nih.gov/pubmed/447618</ref>This study proved that a number of amino acids can inhibit the Argininosuccinate synthetase enzyme. Studies are also being done to identify fumonisin B1 as an inhibitor of argininosuccinate synthetase using fumonisin affinity chromatography and in vitro kinetic studies.The extent of the inhibition of argininosuccinate synthetase in cells, and the possible role of this enzyme inhibition in the cellular toxicity of FB1, remains to be established.<ref>http://www.ncbi.nlm.nih.gov/pubmed/11083085</ref> | ||
===='''Implications'''==== | ===='''Implications'''==== | ||