Seminars Last F John Antos Protein Engineering of Sortases and transacylase reactions
Figure 17-26 Thiamine pyrophosphate. Page 604
Figure 23-3aBiotin and carboxybiotinyl–enzyme. (a) Biotin consists of an imidazoline ring that is cis-fused to a tetrahydrothiophene ring bearing a valerate side chain. Raw eggs contain avidin—a protein with very high affinity for biotin Bacteria (Streptomyces) make avidin analogs like streptavidin—where did we see this recently??? http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/chime/biotin/btn-index.html
Cells’ second energy currency: NADPH! • NADPH is required for reductive biosynthesis • FA’s • Steroids • Photosynthesis • Etc. • NADPH is generated by oxidation of G6P • Pentose phosphate pathway (PPP) = hexose monophosphate shunt= phosphogluconate pathway • 3 G6P + 6 NADP+ + 3 H2O →6 NADPH + 6 H+ + 3 CO2 + 2 F6P = GA3P • Pathway divided into 3 phases • Oxidative Reactions • Produces Ribulose-5-P • Isomerization/Epimerization Reactions • Produces Ribose-5-P and Xyulose-5-P • Transaldolase and Transketolase Reactions • 3 Ru5P ↔r5P + 2 Xu5P Most cells maintain their [NAD+]/[NADPH] near 1000!!!
FIGURE 14-27 Role of NADPH in regulating the partitioning of glucose 6-phosphate between glycolysis and the pentose phosphate pathway. When NADPH is forming faster than it is being used for biosynthesis and glutathione reduction (see Figure 14-20), [NADPH] rises and inhibits the first enzyme in the pentose phosphate pathway. As a result, more glucose 6-phosphate is available for glycolysis.
Lyrics • http://books.google.com/books?id=oq9ENyL_d9YC&lpg=PP1&pg=PA1#v=onepage&q&f=false http://books.google.com/books?id=oq9ENyL_d9YC&lpg=PP1&pg=PA1#v=onepage&q&f=false
David L. Nelson and Michael M. Cox • LEHNINGER • PRINCIPLES OF BIOCHEMISTRY • Fifth Edition CHAPTER 15 Principles of Metabolic Regulation © 2008 W. H. Freeman and Company