Methionine salvage pathway

FIGURE 3.27 Dioxygenation of enediol to formate + CO in the methionine salvage pathway. 

Wray JW, RH Abeles (1995) The methionine salvage pathway in Klebsiella pneumoniae and rat liver. J Biol Chem 270 3147-3153. 

Methionine Salvage Pathway Dioxygenases in Klebsiella pneumoniae 617... 

FIG. 55 Methionine salvage pathway via 5 -methylthioadenosine (MTA). 1, MTA phosphorylase 2, MTA nucleosidase 3, 5-methylthioritese kinase. 

Salim HMW, Negritto MC, Cavalcanti ARO. 1+1=3 A fusion of 2 enzymes in the methionine salvage pathway of Tettahymena thermophila creates a trifunctional enzyme that catalyzes 3 steps in the pathway. PLoS One. 2009 5(10) el000701. doi 10.1371/ joumal.pgen. 1000701. 

Nakano T, Ohki KI, Yokota A, Ashida H. Min BD is a multifunctional fusion enzyme in the methionine salvage pathway of Tetrah5unena thermophila. PLoS One. 2013 8(7) e7385. 

Methylcobalamin is needed for methionine synthase (also known as homocysteine methyltransferase) for the methionine salvage pathway. 

Dai, Y Pochapsky, Th.C. Abeles, R.H. Mechanistic Studies of Two Dioxygenases in the Methionine Salvage Pathway of Klebsiella pneumonia. Biochemistry 2001, 40, 6379-6387. 

M.E. Houston Jr., D.L. Vander Jagt, and JP. Honek, Synthesis and biological activity of fluorinated intermediates of the methionine salvage pathway, Bioorg, Med, Chem, Lett, 1 623 (1991). 

The methionine salvage pathway (MSP) plays a critical role in regulating a munber of important metabolites in prokaryotes and eukaryotes. Acireductone dioxygenases (ARDs) Ni(Fe)ARD are enz mies involved in the methionine recycle pathway, which regulates aspects of the cell cycle. The relatively subtle differences between the two metal protein complexes are amplified by the surrounding protein stmcture, giving two enzymes of different stmctures and activities from a single pol eptide [2-5]. 

The products of the two enz5onatic Acireductone oxidations differ in that one enzyme Fe ARD or ARD ) converts Acireductone to the R-ketoacid precursor of methionine, and formate, while the other enzyme Ni ARD (or ARD) produces methylthiopropionate, CO, and formate. The precise function of the Ni ARD reaction in the K. pneumoniae is unclear. Its products are not precursors for methionine. The Ni ARD-catalyzed reaction may thus be considered a shunt in the methionine salvage pathway, aiding in the regulation of methionine [2-5]. 

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