Problem 1
Give brief descriptions of the following: (a) peptide; (b) naturally occurring amino acids; (c) metalloprotein; (d) apoprotein; (e) haem unit.
Problem 5
(a) Briefly describe the mode of binding of \(\mathrm{O}_{2}\) to the iron centre in one haem unit of haemoglobin. (b) What are 'picket fence' porphyrins and why are they used in model studies of \(\mathrm{O}_{2}\) binding to myoglobin or haemoglobin? (c) The binding of \(\mathrm{O}_{2}\) to haemoglobin exhibits a 'cooperativity' effect. What is meant by this statement? (d) Why is the change from deoxyhaemoglobin to the oxy-form accompanied by a decrease in the observed magnetic moment?
Problem 6
Compare the modes of binding of \(\mathrm{O}_{2}\) to the metal centres in (a) myoglobin, (b) haemerythrin and (c) haemocyanin. Indicate what supporting experimental evidence is available for the structures you describe.
Problem 7
Differentiate between Type \(1,\) Type 2 and Type 3 copper centres in blue copper proteins, giving both experimental and structural distinctions.
Problem 11
What is the mitochondrial electron-transfer chain, and what role do quinones play in the chain?
Problem 16
(a) What is the function of cytochrome \(c\) oxidase? (b) Describe the four active metal-containing sites in cytochrome \(c\) oxidase and the proposed way in which they work together to fulfil the role of the metalloprotein.
Problem 19
The hydrolysis of the acid anhydride 29.31 by \([\mathrm{OH}]^{-}\) is catalyzed by \(\mathrm{Zn}^{2+}\) ions. The rate equation is of the form: \\[ \text { Rate }=k[\mathbf{2 9 . 3 1}]\left[\mathrm{Zn}^{2+}\right]\left[\mathrm{OH}^{-}\right] \\] It is also known that the addition of \(\mathrm{Zn}^{2+}\) does not accelerate hydrolysis by \(\mathrm{H}_{2} \mathrm{O}\) or attack by other nucleophiles. Suggest a mechanism for this reaction.
