Chapter 6, Problem 24DAP

(a)

Summary Introduction

To determine: An explanation to mutation in LDH which replaces Arg¹⁰⁹ with Gln and shows 5% of pyruvate binding and 0.07% wild-type enzyme activity.

Introduction:

Mutation in an organism is defined as a permanent alteration of “nucleotide sequences”. The mutations can be harmful, beneficial or neutral depending on the location of alteration in the genome and the effect exerted by the environment.

(b)

Summary Introduction

To determine: The reason why it is a surprising effect when the mutant form of LDH in which Arg¹⁷¹ is replaced with Lys shows only 0.05% of the wild –type level of substrate level binding.

Introduction:

Amino acids are building blocks of proteins. It is an organic compound that contains an amine group and carboxyl group along with a functional R group. It is involved in the regulation of several cellular processes of the body.

(c)

Summary Introduction

To explain: The effect of substituting Arg¹⁷¹with Lys.

Introduction:

Amino acids are building blocks of proteins. It is an organic compound that contains an amine group and carboxyl group along with a functional R group. It is involved in the regulation of several cellular processes of the body.

(d)

Summary Introduction

To explain: The reason why the mutant form of LDH in which Ile²⁵⁰ is replaced by Gln shows reduced binding of NADH.

Introduction:

Lactate dehydrogenase is a type of enzyme which is found in all living organisms including plants, animals and other prokaryotes. It is involved in the conversion of lactate into pyruvic acid in a cell.

(e)

Summary Introduction

To sketch: The active site of mutant LDH with oxaloacetate bound.

Introduction:

Lactate dehydrogenase is a type of enzyme which is found in all living organisms including plants, animals and other prokaryotes. It is involved in the conversion of lactate into pyruvic acid in a cell.

(f)

Summary Introduction

To determine: The use of oxaloacetate by mutant enzyme as a substrate instead of pyruvate.

Introduction:

Oxaloacetate is an organic compound and is an intermediate of citric acid cycle which reacts with acetyl-CoA to form citrate. The enzyme involved in this conversion is citrate synthase.

(g)

Summary Introduction

To explain: The statement that substituting a larger amino acid in the active site allowed a larger substrate to bind.

Introduction:

Amino acids are building blocks of proteins. It is an organic compound that contains an amine group and carboxyl group along with a functional R group. It is involved in the regulation of several cellular processes of the body.