Down mutations to decrease promoter efficiency usually decrease conformance to the consensus sequences, whereas up mutations have the opposite effect.

 Mutations in the -35 sequence can affect initial binding of RNA polymerase.

Mutations in the -10 sequence can affect binding or the melting reaction that converts a closed to an open complex.

TLS Online TPP Program

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#Unit 1. Molecules and their Interaction Relevant to Biology

Secondary plots for competitive inhibition.

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#Unit 1. Molecules and their Interaction Relevant to Biology

Therefore, at fixed [S0], a plot of 1/v0 against [Io] (the Dixon plot) is linear. When [Io] = -Ki , it can be seen that 1/v0 = l!V max and is therefore independent of [S0], so Dixon plots for different values of [So] (but fixed [Eo]) intersect where [lo] = -Ki

TLS Online TPP Program

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#Unit 1. Molecules and their Interaction Relevant to Biology

TLS Online TPP Program

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#Unit 1. Molecules and their Interaction Relevant to Biology

Lineweaver-Burk plot showing the effect of uncompetitive inhibition; (b) the same, showing plots for several inhibitor concentrations at fixed enzyme concentration.

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#Unit 1. Molecules and their Interaction Relevant to Biology

Non-competitive inhibition 

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#Id: 4932

#Unit 1. Molecules and their Interaction Relevant to Biology

A non-competitive inhibitor can combine with an enzyme molecule to produce a dead-end complex.