Assignment 2: Galactose Operon of E. coli
FS 8404
Professor Mustapha
Of some 4,000 genes in Escherichia coli (E. coli), only a handful are expressed at a time1. This regulation in gene expression helps cells function more efficiently. To provide the cell with energy, glucose is the most highly desired source. However, in the absence of glucose and the presence of other sugars, operons regulate gene expression to code for enzymes that can help utilize the sugar as energy in the cell1. Galactose is a monosaccharide that is often a byproduct of lactose hydrolyzation. The following looks at the Gal operon in E. coli.
Galactose utilization in E. coli goes through the Leloir pathway to convert galactose into glucose-1-phosphate2. Depending on …show more content…
Holden et al. (2003) describes the different genes coding for enzymes and their functions, GalM codes for aldose-1-epimerase, the enzyme responsible for converting β-D-galactose into α-D-galactose. The next step of the Leloir pathway is converting α-D-galactose to galactose-1-phosphate which requires Galactokinase. Galactokinase is encoded by the galK gene. Next, galactose-1-phosphate is converted into UDP glucose via galactose-1-phosphateuridylyl transferase encoded by galT. Lastly, glucose-1-phosphateuridylyl transferase converts UDP glucose into glucose-1-phoshate. This enzyme is encoded by the galE gene.
References
1. Lehninger, Albert L, David L Nelson, and Michael M Cox. Lehninger Principles Of Biochemistry. 1st ed. New York: W.H. Freeman, 2005. Print.
2. Holden, H. M., I. Rayment, and J. B. Thoden. "Structure And Function Of Enzymes Of The Leloir Pathway For Galactose Metabolism". Journal of Biological Chemistry 278.45 (2003): 43885-43888. Web. 26 Jan. 2017.
3. "Gal Operon (Molecular Biology)". What-when-how.com. N.p., 2017. Web. 29 Jan. 2017.
4. Weickert, M J and S Adhya. "Control Of Transcription Of Gal Repressor And Isorepressor Genes In Escherichia Coli.". Journal of Bacteriology 175.1 (1993): 251-258.
FS 8404
Professor Mustapha
Of some 4,000 genes in Escherichia coli (E. coli), only a handful are expressed at a time1. This regulation in gene expression helps cells function more efficiently. To provide the cell with energy, glucose is the most highly desired source. However, in the absence of glucose and the presence of other sugars, operons regulate gene expression to code for enzymes that can help utilize the sugar as energy in the cell1. Galactose is a monosaccharide that is often a byproduct of lactose hydrolyzation. The following looks at the Gal operon in E. coli.
Galactose utilization in E. coli goes through the Leloir pathway to convert galactose into glucose-1-phosphate2. Depending on …show more content…
Holden et al. (2003) describes the different genes coding for enzymes and their functions, GalM codes for aldose-1-epimerase, the enzyme responsible for converting β-D-galactose into α-D-galactose. The next step of the Leloir pathway is converting α-D-galactose to galactose-1-phosphate which requires Galactokinase. Galactokinase is encoded by the galK gene. Next, galactose-1-phosphate is converted into UDP glucose via galactose-1-phosphateuridylyl transferase encoded by galT. Lastly, glucose-1-phosphateuridylyl transferase converts UDP glucose into glucose-1-phoshate. This enzyme is encoded by the galE gene.
References
1. Lehninger, Albert L, David L Nelson, and Michael M Cox. Lehninger Principles Of Biochemistry. 1st ed. New York: W.H. Freeman, 2005. Print.
2. Holden, H. M., I. Rayment, and J. B. Thoden. "Structure And Function Of Enzymes Of The Leloir Pathway For Galactose Metabolism". Journal of Biological Chemistry 278.45 (2003): 43885-43888. Web. 26 Jan. 2017.
3. "Gal Operon (Molecular Biology)". What-when-how.com. N.p., 2017. Web. 29 Jan. 2017.
4. Weickert, M J and S Adhya. "Control Of Transcription Of Gal Repressor And Isorepressor Genes In Escherichia Coli.". Journal of Bacteriology 175.1 (1993): 251-258.