• Dissociating Enzymes
• UMP Synthase
• Uridine Kinase
• Beta-alanine Synthase
• Purine & Pyrimidine Concentrations
Allosteric Regulatory Enzymes
T. Traut, 2008, Springer Science
About this book
* Covers recent developments in the analysis of allosteric enzymes
All enzymes are remarkable since they have the ability to increase the rate of a chemical reaction, often by more than a billion-fold. Allosteric enzymes are even more amazing because the have the additional ability to change their rate in response to cellular activators or inhibitors. This enables them to control the pathway in which they are the regulatory enzyme. Since the effector molecules represent the current status of the cell for a given metabolic pathway, this results in very responsive and balanced metabolic states, and makes it possible for cells and organisms to be appropriately dynamic, and responsive, in a changing environment. This book provides a logical introduction to the limits for enzyme function as dictated by the factors that are the limits for life. This book presents a complete description of all the mechanisms used for changing enzyme acticity. Eight enzymes are used as model systems after extensive study of their mechanisms. Wherever possible, the human form of the enzyme is used to illustrate the regulatory features.
While authors often emphasize the few enzymes that have the most remarkable catalytic rates, this survery of enzymes has led to the author's appreciation of some important, general conclusions:
1. Most enzymes are not exceptionally fast; they are always good enough for their specific catalytic step.
2. Although enzymes could always be much faster if they changed so as to bind their substrates more weakly, actual enzymes must be able to discriminate in favor of their special substrate, and therefore they have sacrificed speed to obtain better binding. This means that specific control of individual metabolic steps is more important than overall speed.
3. Results for many hundreds of enzymes establish that a lower limit for a normal catalytic activity is 1 s-1. Most enzymes have a catalytic rate between 10 and 300 s-1.4. Allosteric regulation always results in a change in the enzymes's affinity for its substrate. Even V-type enzymes (named for their large change in catalytic velocity) always have a corresponding change in affinity for their substrate.
Review of this book: "This holistic introduction to enzymes in general covers the history of their discovery and the different mechanisms of action before going into an in-depth presentation of particular allosteric enzymes and enzyme families. … This book will be of great help to graduate students and postdoctoral fellows interested in understanding the theory behind the action of allosteric enzymes. … an excellent book of enzymology focusing on the mechanisms employed by allosteric enzymes and their metabolic regulation." (Helen Anni, Doody’s Review Service, October, 2008)
Allosteric Enzymes in Pyrimidine Metabolism
1. Traut, T.W. and Temple, B.R.S. (2000) The chemistry of the reaction determines the invariant amino acids during the evolution and divergence of orotidine 5'-monophosphate decarboxylase. J. Biol. Chem. 275, 28675-28681.
2. Najarian, T. and Traut, T.W. (2000) Nifedipine and nimodipine competitively inhibit uridine kinase and orotidine-phosphate decarboxylase, vital in nerve cell membrane repair. Neurorehabil. Neur. Repair14, 237-241.
3. Ropp, P.A. and Traut, T.W. (1998) Uridine kinase: altered enzyme with decreased affinities for uridine and CTP. Arch. Bioch. Biophys. 359, 63-68.
4. Miller, B.G., Traut, T.W., and Wolfenden, R. (1998) Effects of substrate binding determinants in the transition state for OMP decarboxylase. Bioorganic Chem.26, 283-288.
5. Traut, T.W. and Jones, M.E. (1996) Uracil metabolism: UMP synthesis from orotic acid or uridine and conversion of uracil to beta-alanine: Enzymes and cDNAs. Prog. Nuc. Acid Res. Mol.Biol.53, 1- 78.
6. Yablonski, M. J., Pasek, D. A., Han, B.-D., Jones, M. E., & Traut, T. W. (1996) Intrinsic activity and stability of bifunctional UMP synthase, and of its two separate domains, orotate phosphoribosyl-transferase and orotidine-5'-phosphate decarboxylase. J. Biol. Chem.271, 10704-10708.
7. Ropp, P.K. and Traut, T.W. (1996) Cloning and expression of a cDNA encoding uridine kinase from mouse brain. Arch. Bioch.Biophys. 336, 105-112.
8. Traut, T.W. (1994) Dissociation of enzyme oligomers: A mechanism for allosteric regulation. CRC Crit. Rev. Biochem. Mol. Biol.29, 125-163.
9. Traut, T.W. (1994) The functions and consensus motifs of 9 types of peptide segments that form different types of nucleotide binding sites. Eur. J. Biochem. 222, 9-19.
10. Traut, T.W. (1994) Physiological concentrations of purines and pyrimidines. Molec. Cell. Biochem. 140, 1-22.
11. Matthews, M.M., Liao, W., Kvalnes-Krick, K.L., and Traut, T.W. (1992) Beta-alanine Synthase: Purification and allosteric properties. Arch. Biochem. Biophys. 293, 254-263.
12. Kvalnes-Krick, K.L., and Traut, T.W. (1993) Cloning, sequencing, and expression of a cDNA encoding beta-alanine synthasefrom rat liver. J. Biol. Chem. 268, 5686-5693.
13. Ropp, PK and Traut, T.W. (1991) Purine nucleoside phosphorylase: Allosteric regulation of a dissociating enzyme. J. Biol. Chem.266, 7682-7687.
14. Ropp, P.K. and Traut, T.W. (1991) Allosteric regulation of purine nucleoside phosphorylase. Arch. Biochem. Biophys. 288, 614-620.
15. Traut, T.W. (1989) Uridine-5'-phosphate Synthase: Evidence for substrate cycling involving this bifunctional protein. Arch. Biochem. Biophys. 268, 108-115.
16. Traut, T.W. (1988) Do exons code for structural or functional units in proteins? Proc. Natl. Acad. Sci. USA 85, 2944-2948.
17. Traut, T.W. (1988) Enzymes of nucleotide metabolism: The significance of subunit size size for biological function and regulatory properties. CRC Crit. Rev. Biochem.23, 121-169.