Seminars

Last F John Antos

Protein Engineering of Sortases and transacylase reactions

Figure 17-24 Reaction mechanism of lactate dehydrogenase.

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Figure 17-25 The two reactions of alcoholic

fermentation.

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Figure 17-26 Thiamine pyrophosphate.

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Figure 23-3a Biotin 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 biotinBacteria (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

Pentose Phosphate Pathway!

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!!!

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3Figure 23-25 The pentose phosphate pathway.

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.

PPP Song

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

• LEHNINGER • PRINCIPLES OF BIOCHEMISTRY

• Fifth Edition

David L. Nelson and Michael M. Cox

© 2008 W. H. Freeman and Company

CHAPTER 15Principles of Metabolic Regulation

“Alfonse, Biochemistry makes my head hurt!!”\