Chemistry Reference
In-Depth Information
Figure 7.18
These biological washing powders contain enzymes.
There were problems associated with the early
biological washing powders. Some customers suffered
from skin rashes, because they were allergic to the
enzymes (Figure 7.19). This problem has been
overcome to a certain extent by advising that extra
rinsing is required. Also, many manufacturers have
placed warnings on their packets, indicating that
the powder contains enzymes which may cause skin
rashes.
Figure 7.17
The enzyme molecules (red, pink, green and blue) lock on
exactly to a particular reactant molecule (yellow). Once the enzyme is
locked on, the reactant molecule breaks up into pieces.
For example, hydrogen peroxide is produced within
our bodies. However, it is extremely damaging and
must be decomposed very rapidly. Catalase is the
enzyme which converts hydrogen peroxide into
harmless water and oxygen within our livers:
hydrogen peroxide
catalase
water + oxygen
2H
2
O
2
(
aq
)
catalase
2H
2
O(
l
) + O
2
(
g
)
Although many chemical catalysts can work under
various conditions of temperature and pressure as
well as alkalinity or acidity, biological catalysts operate
only under very particular conditions. For example,
they operate over a very narrow temperature range
and if the temperature becomes too high, they
become inoperative. At temperatures above about
45 °C, they denature. This means that the specific
shape of the active site of the enzyme molecule
changes due to the breaking of bonds. This means
that the reactant molecules are no longer able to fit
into the active site.
A huge multimillion-pound industry has grown
up around the use of enzymes to produce new
materials. Biological washing powders (Figure 7.18)
contain enzymes to break down stains such as sweat,
blood and egg, and they do this at the relatively low
temperature of 40 °C. This reduces energy costs,
because the washing water does not need to be
heated as much.
Figure 7.19
An allergic reaction to a biological detergent.
Other industrial processes also make use of enzymes.
●
In the manufacture of baby foods, enzymes called
proteases are used to 'pre-digest' the protein part
of the baby food. This is because young babies are
unable to digest protein molecules.
●
The enzyme isomerase is used to convert glucose
syrup to fructose syrup. Fructose syrup is much
sweeter than glucose syrup and can be used as a
sweetener in slimming foods as less is needed.
