Investigating the Effect of Enzyme Concentration on the Hydrolysis of Starch with Amylase

Investigating the Effect of Enzyme Concentration on the Hydrolysis of Starch with Amylase

Aim: Investigate the effect of enzyme concentration on the rate of an

enzyme-controlled reaction. Using amylase and starch as my example.

Introduction: I am investigating the effect of the concentration of

the enzyme, amylase on the time taken for the enzyme to fully

breakdown the substrate, starch to a sugar solution. The varied

variable will be the concentration and all other variables are going

to be fixed. The different concentrations will be: 0.5% 0.75% 1.0%

1.5% 2%

An enzyme is a class of protein, which acts as a biological catalyst

to speed up the rate of reaction with its substrates. Enzymes have the

ability to act on a small group of chemically similar substances.

Enzymes are very specific, in the sense that each enzyme is limited to

interact with only one set of reactants; the reactants are referred to

as substrates. Substrates of an enzyme are the chemicals altered by

enzyme-catalysed reactions. The extreme specific nature of enzymes are

because of the complicated three-dimensional shape, which is due to

the particular way the amino acid chain of proteins folds. The

three-dimensional contour limits the number of substrates that can

possibly react to only those substrates that can specifically fit the

enzyme surface. Enzymes have an active site, which is the specific

indent caused by the amino acid on the surface that fold inwards. The

active site only allows a substrate of the exact unique shape to fit;

this is where the substance combines to form an enzyme- substrate

complex. Forming an enzyme-substrate complex makes it possible for

substrate molecules to combine to form a product. In this experiment,

the product is maltose.

The 'lock and key' hypothesis explains how enzymes only work with a

specific substrate. The hypothesis presents the enzyme as the 'lock,

and the specific substrate as 'key'. The active site binds the

substrate, forms a product, which is then released.

Diagram 1- a diagram showing the 'lock and key' mechanism works