Investigation on the Enzyme Trypsin

Investigation on the Enzyme Trypsin

An Investigation determining a factor affecting the rate of digestion

of gelatin by the protease trypsin.

Introduction

An enzyme is a biological catalyst, which speeds up reactions. An

example of this in the human body is trypsin (a protease produced in

the pancreas and used in the stomach), which catalyses the digestion

of gelatine, a protein. For this investigation, a photographic film

will be the source of the gelatine. I will be able to identify when

the gelatine is digested, when the photographic film turns from a dark

brown colour, to being transparent.

All enzymes are proteins, which are specific to the molecule that they

break down. This is known as the ‘lock and key’ theory, where the

active site only allows a specific substrate to be broken down,

eventually resulting in easier absorption (larger surface area).

Enzymes are made up of a long chain of amino acids, which form

together in such a way as to leave a specific pocket, into which a

substrate (as long as it fits perfectly into the pocket) can fit into

it like a key in a lock (hence the ‘lock and key’ theory). The

reaction then takes place, and the product of the substrate is then

released. The enzyme, not changed by the reaction, can then perform

the same “operation” on countless other substrates.

Because the enzyme can be re-used, only a small amount is needed.

Despite this enzymes can make cell reactions go many million times

faster than they would normally. Since enzymes are biological

catalysts, by definition, they are not used up or changed in the

reaction that they catalyse. Even though they cannot be used up, when...

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the amount of time that the gelatin spent outside the trypsin, and I

would ignore the result of the other experiment. This, I feel, would

improve the accuracy of my experiment, and would probably supply more

constant results.

In order to extend my investigation, I would investigate the

denaturisation of trypsin at 60°C, and see if expediential decay still

occurred. I would first wait until the temperature had reached 60°C

(this would take a few minutes), and then start timing, because before

the trypsin reaches 60°C, the results produced cannot be formed into a

conclusion analysing trypsin at 60°C, as the trypsin would never have

reached 60°C. (This also leads into the problem that waiting a few

minutes for the trypsin to warm up would result in some of the trypsin

becoming denatured before timing had started).