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Introduction to Enzyme and Coenzyme Chemistry - E-Library Home

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270 Chapter 12<br />

Problems<br />

(1) How reversible do you think the Tetrahymena ribozyme-catalysed selfsplicing<br />

reaction is What is the potential signiWcance of the reverse<br />

reaction<br />

(2) Suggest a hapten that could be used <strong>to</strong> induce catalytic antibodies for the<br />

lac<strong>to</strong>nisation reaction below.<br />

O<br />

NO 2<br />

O<br />

O<br />

O<br />

+<br />

NO 2<br />

R<br />

OH<br />

R<br />

HO<br />

(3) Explain why the hapten below elicited antibodies capable of catalysing the<br />

elimination reaction shown.<br />

hapten<br />

N<br />

CONH-protein<br />

O 2 N<br />

reaction<br />

F<br />

O<br />

O<br />

O 2 N<br />

O 2 N<br />

(4) What type of catalytic properties would you expect from a cyclodextrin<br />

covalently modiWed with: (i) a thiol group; (ii) a riboXavin group (Note:<br />

reduced riboXavin is rapidly oxidised by dioxygen in aerobic solutions)<br />

Further reading<br />

Catalytic RNA<br />

T.R. Cech & B.L. Bass (1986) Biological catalysis by RNA. Annu. Rev. Biochem., 55,<br />

599–630.<br />

T.R. Cech, D. Herschlag, J.A. Piccirilli & A.M. Pyle (1992) RNA catalysis by a group<br />

I ribozyme. J. Biol. Chem., 267, 17479–82.<br />

P. Nissen, J. Hansen, N. Ban, P.B. Moore & T.A. Steitz (2000) The structural basis of<br />

ribosome activity in peptide bond synthesis. Science, 289, 920–30.

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