Enzymes
UniProtKB help_outline | 43,959 proteins |
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- Name help_outline carbamoyl phosphate Identifier CHEBI:58228 (CAS: 63082-13-3) help_outline Charge -2 Formula CH2NO5P InChIKeyhelp_outline FFQKYPRQEYGKAF-UHFFFAOYSA-L SMILEShelp_outline NC(=O)OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 17 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline L-aspartate Identifier CHEBI:29991 Charge -1 Formula C4H6NO4 InChIKeyhelp_outline CKLJMWTZIZZHCS-REOHCLBHSA-M SMILEShelp_outline [NH3+][C@@H](CC([O-])=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 74 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline N-carbamoyl-L-aspartate Identifier CHEBI:32814 Charge -2 Formula C5H6N2O5 InChIKeyhelp_outline HLKXYZVTANABHZ-REOHCLBHSA-L SMILEShelp_outline NC(=O)N[C@@H](CC([O-])=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 4 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline phosphate Identifier CHEBI:43474 Charge -2 Formula HO4P InChIKeyhelp_outline NBIIXXVUZAFLBC-UHFFFAOYSA-L SMILEShelp_outline OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 992 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:20013 | RHEA:20014 | RHEA:20015 | RHEA:20016 | |
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Publications
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Structure and mechanisms of Escherichia coli aspartate transcarbamoylase.
Lipscomb W.N., Kantrowitz E.R.
Enzymes catalyze a particular reaction in cells, but only a few control the rate of this reaction and the metabolic pathway that follows. One specific mechanism for such enzymatic control of a metabolic pathway involves molecular feedback, whereby a metabolite further down the pathway acts at a un ... >> More
Enzymes catalyze a particular reaction in cells, but only a few control the rate of this reaction and the metabolic pathway that follows. One specific mechanism for such enzymatic control of a metabolic pathway involves molecular feedback, whereby a metabolite further down the pathway acts at a unique site on the control enzyme to alter its activity allosterically. This regulation may be positive or negative (or both), depending upon the particular system. Another method of enzymatic control involves the cooperative binding of the substrate, which allows a large change in enzyme activity to emanate from only a small change in substrate concentration. Allosteric regulation and homotropic cooperativity are often known to involve significant conformational changes in the structure of the protein. Escherichia coli aspartate transcarbamoylase (ATCase) is the textbook example of an enzyme that regulates a metabolic pathway, namely, pyrimidine nucleotide biosynthesis, by feedback control and by the cooperative binding of the substrate, L-aspartate. The catalytic and regulatory mechanisms of this enzyme have been extensively studied. A series of X-ray crystal structures of the enzyme in the presence and absence of substrates, products, and analogues have provided details, at the molecular level, of the conformational changes that the enzyme undergoes as it shifts between its low-activity, low-affinity form (T state) to its high-activity, high-affinity form (R state). These structural data provide insights into not only how this enzyme catalyzes the reaction between l-aspartate and carbamoyl phosphate to form N-carbamoyl-L-aspartate and inorganic phosphate, but also how the allosteric effectors modulate this activity. In this Account, we summarize studies on the structure of the enzyme and describe how these structural data provide insights into the catalytic and regulatory mechanisms of the enzyme. The ATCase-catalyzed reaction is regulated by nucleotide binding some 60 Å from the active site, inducing structural alterations that modulate catalytic activity. The delineation of the structure and function in this particular model system will help in understanding the molecular basis of cooperativity and allosteric regulation in other systems as well. << Less
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Studies on the biosynthesis of carbamylaspartic acid.
Lowenstein J.M., Cohen P.P.
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ASPARTATE TRANSCARBAMYLASE, AN ENZYME DESIGNED FOR FEEDBACK INHIBITION.
GERHART J.C., PARDEE A.B.