Molecular Biochemistry II

Amino Acid Catabolism - Nitrogen


Textbook Reading: Voet & Voet, Biochemistry, 3rd Edition, p. 985-995.

Some recent articles (optional reading): 
G. Schneider, H. Kck & Y. Lindqvist (2000) "The manifold of vitamin B6 dependent enzymes," Structure 8: R1-R6.
X. Huang, H. M. Holden & F. M. Raushel (2001) "Channeling of substrates and intermediates in enzyme-catalyzed reactions," Annu. Rev. Biochem 70: 149-180.
S. M. Morris (2002) "Regulation of enzymes of the urea cycle and arginine metabolism," Annu. Rev. Nutr. 22: 87-105.
H. Hayashi, H. Mizuguchi, I. Miyahara, M. M. Islam, H. Ikushiro, Y. Nakajima, K. Hirotsu & H. Kagamiyama (2003) "Strain and catalysis in aspartate aminotransferase," Biochim. Biophys. Acta 1647: 103-109.
L. Caldovic & M. Tuchman (2003) "N-Acetylglutamate and its changing role through evolution," Biochem. J. 372: 279-290.
A. Husson, C. Brasse-Lagnel, A. Fairand, S. Renouf & A. Lavoinne (2003) "Argininosuccinate synthetase from the urea cycle to the citrulline-NO cycle," Eur. J. Biochem. 270: 1887-1899.
J. Jnne, L. Alhonen, M. Pietil & T. A. Keinnen (2004) "Genetic approaches to the cellular functions of polyamines in mammals," Eur. J. Biochem. 271: 877-894.
D. J. Stuehr, J. Santolini, Z.-Q. Wang, Chin-Chuan Wei & S. Adak (2004) "Update on mechanism and catalytic regulation in the NO synthases," J. Biol. Chem. 279: 36167-36170.
B.-Y. Hwang, B.-K. Cho, H. Yun, K. Koteshwar & B.-G. Kim (2005) "Revisit of aminotransferase in the genomic era and its application to biocatalysis," J. Molec. Catalysis B: Enzymatic 37: 47-55.
B. Gyorgy, E. Toth, E. Tarcsa, A. Falus & E. I. Buzas (2006) "Citrullination: A posttranslational modification in health and disease," Internat. J. Biochem & Cell Biol. 38: 1662-1677.
S. Lamas, C. J. Lowenstein & T. Michel (2007) "Nitric oxide signaling comes of age: 20 years and thriving," Cardiovascular Res. 75: 207-209 (and accompanying articles).
A. C. F. Gorren & B. Mayer (2007) Nitric-oxide synthase: A cytochrome P450 family foster child," Biochim. Biophys. Acta 1770: 432-445.
P. Pacher, J. S. Beckman & L. Liaudet (2007) "Nitric oxide and peroxynitrite in health and disease," Physiol. Rev. 87: 315-424.
T. Kuhara (2007) "Noninvasive human metabolome analysis for differential diagnosis of inborn errors of metabolism," J. Chromatography B 855: 42-50.

Potential Test Questions:

1. Write out the reactions by which the transaminase (aminotransferase) and glutamate dehydrogenase enzymes work together to deaminate amino acids consumed in excess of nutritional needs. Include structures of substrates and products of both reactions, using a specific example for the transaminase reaction.

2.a. Write out the individual steps of the reaction catalyzed by the mitochondrial enzyme Carbamoyl Phosphate Synthase I, giving names and structures of reactants and products for each of the three steps. (Structure of ATP may be omitted.)
b. What compound causing mental retardation is elevated in the blood if this enzyme is inadequate? How might hereditary deficiency of Carbamoyl Phosphate Synthase be treated? Explain.

3. Diagram and describe the reaction sequence during catalysis by transaminase (aminotransferase) enzyme, including structures of different forms of the active site cofactor, substrates and products. For your diagrams, assume that alanine is the amino group donor and a-ketoglutarate is the acceptor.

Copyright 1998-2008 by Joyce J. Diwan. All rights reserved.

Lecture Notes on
Amino Acid Catabolism: N

Interactive Quiz on     
   Amino Acid Catabolism (N)

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