Use phosphate-buffered solutions in experiments | Homework Helpers

1. Biologists frequently use phosphate-buffered solutions in experiments.  You need to prepare a sodium phosphate solution at pH 6.7 by mixing NaH2PO4 and Na2HPO4 (pKa =7.2).  What are the respective concentration of each of these substances if you want the final concentration of phosphate ([HPO4-2]+[H2PO4-] to be 150 mM?

2. Activity of the bacterial enzyme acetoacetate decarboxylase sharply declines below pH 6, suggesting there is an ionizable catalytic residue with pKa ~ 6. Using mutagenesis, this critical catalytic residue was determined to be Lys-115.

Don't use plagiarized sources. Get Your Custom Essay on
Use phosphate-buffered solutions in experiments | Homework Helpers
Get an essay WRITTEN FOR YOU, Plagiarism free, and by an EXPERT!
Order Essay

MCB354FA15_PS01

a) For catalytic Lys-115, what is the ratio of deprotonated to protonated side chain at pH 7.5?

b) The neighboring residue at position 116 is also lysine. Explain how this perturbs the pKa of the catalytic lysine residue.

superadmin

Recent Posts

LDR 3302-21.01.01-1A24-S1, Organizational Theory and Behavior

LDR 3302-21.01.01-1A24-S1, Organizational Theory and Behavior Unit III Essay Top of Form Bottom of Form…

3 years ago

Psychology Question | My Essay Helpers

Chapter 9 What are teratogens? Give 5 examples. Define each of these stages: Germinal, embryonic,…

4 years ago

Financial Market Analysis | My Essay Helpers

You are a Financial Analyst that has been appointed to lead a team in the…

4 years ago

Decision theory | My Essay Helpers

This week’s discussion will focus on management decision-making and control in two companies, American corporation…

4 years ago

Literature Question | My Essay Helpers

Mary Rowlandson felt that the man who eventually came to own her, Quinnapin, was “the…

4 years ago