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The Urea Carboxylase And Allophanate Hydrolase Activities Of Urea Amidolyase Are Functionally Independent, Yi Lin, Cody J. Boese, Martin St. Maurice
The Urea Carboxylase And Allophanate Hydrolase Activities Of Urea Amidolyase Are Functionally Independent, Yi Lin, Cody J. Boese, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Urea amidolyase (UAL) is a multifunctional biotin-dependent enzyme that contributes to both bacterial and fungal pathogenicity by catalyzing the ATP-dependent cleavage of urea into ammonia and CO2. UAL is comprised of two enzymatic components: urea carboxylase (UC) and allophanate hydrolase (AH). These enzyme activities are encoded on separate but proximally related genes in prokaryotes while, in most fungi, they are encoded by a single gene that produces a fusion enzyme on a single polypeptide chain. It is unclear whether the UC and AH activities are connected through substrate channeling or other forms of direct communication. Here, we use …
The Role Of Biotin And Oxamate In The Carboxyltransferase Reaction Of Pyruvate Carboxylase, Adam D. Lietzan, Yi Lin, Martin St. Maurice
The Role Of Biotin And Oxamate In The Carboxyltransferase Reaction Of Pyruvate Carboxylase, Adam D. Lietzan, Yi Lin, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. During catalysis, carboxybiotin is translocated to the carboxyltransferase domain where the carboxyl group is transferred to the acceptor substrate, pyruvate. Many studies on the carboxyltransferase domain of PC have demonstrated an enhanced oxaloacetate decarboxylation activity in the presence of oxamate and it has been shown that oxamate accepts a carboxyl group from carboxybiotin during oxaloacetate decarboxylation. The X-ray crystal structure of the carboxyltransferase domain from Rhizobium etli PC reveals that oxamate is positioned in the active site …
Functionally Diverse Biotin-Dependent Enzymes With Oxaloacetate Decarboxylase Activity, Adam D. Lietzan, Martin St. Maurice
Functionally Diverse Biotin-Dependent Enzymes With Oxaloacetate Decarboxylase Activity, Adam D. Lietzan, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Biotin-dependent enzymes catalyze carboxylation, decarboxylation and transcarboxylation reactions that participate in the primary metabolism of a wide range of organisms. In all cases, the overall reaction proceeds via two half reactions that take place in physically distinct active sites. In the first half-reaction, a carboxyl group is transferred to the 1-N′ of a covalently tethered biotin cofactor. The tethered carboxybiotin intermediate subsequently translocates to a second active site where the carboxyl group is either transferred to an acceptor substrate or, in some bacteria and archaea, is decarboxylated to biotin and CO2 in order to power the export of sodium …
A Substrate-Induced Biotin Binding Pocket In The Carboxyltransferase Domain Of Pyruvate Carboxylase, Adam D. Lietzan, Martin St. Maurice
A Substrate-Induced Biotin Binding Pocket In The Carboxyltransferase Domain Of Pyruvate Carboxylase, Adam D. Lietzan, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Biotin-dependent enzymes catalyze carboxyl transfer reactions by efficiently coordinating multiple reactions between spatially distinct active sites. Pyruvate carboxylase (PC), a multifunctional biotin-dependent enzyme, catalyzes the bicarbonate- and MgATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To complete the overall reaction, the tethered biotin prosthetic group must first gain access to the biotin carboxylase domain and become carboxylated and then translocate to the carboxyltransferase domain, where the carboxyl group is transferred from biotin to pyruvate. Here, we report structural and kinetic evidence for the formation of a substrate-induced biotin binding pocket in the carboxyltransferase domain of …
The Enzymes Of Biotin Dependent Co(2) Metabolism: What Structures Reveal About Their Reaction Mechanisms, Grover L. Waldrop, Hazel M. Holden, Martin St. Maurice
The Enzymes Of Biotin Dependent Co(2) Metabolism: What Structures Reveal About Their Reaction Mechanisms, Grover L. Waldrop, Hazel M. Holden, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Biotin is the major cofactor involved in carbon dioxide metabolism. Indeed, biotin-dependent enzymes are ubiquitous in nature and are involved in a myriad of metabolic processes including fatty acid synthesis and gluconeogenesis. The cofactor, itself, is composed of a ureido ring, a tetrahydrothiophene ring, and a valeric acid side chain. It is the ureido ring that functions as the CO2 carrier. A complete understanding of biotin-dependent enzymes is critically important for translational research in light of the fact that some of these enzymes serve as targets for anti-obesity agents, antibiotics, and herbicides. Prior to 1990, however, there was a …
Inhibitors Of Pyruvate Carboxylase, Tonya N. Zeczycki, Martin St. Maurice, Paul V. Attwood
Inhibitors Of Pyruvate Carboxylase, Tonya N. Zeczycki, Martin St. Maurice, Paul V. Attwood
Biological Sciences Faculty Research and Publications
This review aims to discuss the varied types of inhibitors of biotin-dependent carboxylases, with an emphasis on the inhibitors of pyruvate carboxylase. Some of these inhibitors are physiologically relevant, in that they provide ways of regulating the cellular activities of the enzymes e.g. aspartate and prohibitin inhibition of pyruvate carboxylase. Most of the inhibitors that will be discussed have been used to probe various aspects of the structure and function of these enzymes. They target particular parts of the structure e.g. avidin – biotin, FTP – ATP binding site, oxamate – pyruvate binding site, phosphonoacetate – binding site of the …