Amylase, Catalase and Invertase Enzyme Labs

IB Biology SL Y1
22 April 2014

Amylase, Catalase and Invertase Enzyme Labs

Catalase is responsible for converting hydrogen peroxide1, which is harmful within living organisms, into water and oxygen molecules. This experiment investigates the effect of hydrogen peroxide on boiled and raw materials such as potatoes, liver, yeast cells, etc. If boiled materials were put into hydrogen peroxide, there would be no significant enzymatic reaction because the boiling temperature would already denature catalase in those materials, preventing any enzymes from functioning properly.

Sucrose is hydrolyzed into monosaccharide form of fructose and glucose by invertase that catalyzes the hydrolysis1. Invertase can be obtained from yeast, which will be used in this experiment. The yeast suspension solution will show positive result to Benedict’s solution test that indicates the presence of sugar.

Amylase is an enzyme that breaks down starch into glucose through the process of hydrolysis2. It initiates the breakdown of starch to glucose in seeds during germination. To identify the presence of starch, iodine test will be used. If the result shows no color change into deep purple, that indicates the absence of starch and implies the presence of glucose that is broken down from starch. Boiled corn seeds would show least amount of color change in agar plate (from dark purple into transparent) because the high temperature would have already denatured amylase in seeds.

Aim of experiment
These three enzyme experiments aim to investigate each enzyme’s role in breaking macromolecules into simple molecules of smaller units.

Data collection
Table 1.0 – Qualitative observation of catalase lab
Material/extract being tested Boiled extract’s reaction on H2O2 Raw extract’s reaction on H¬¬¬2O2

(No apparent reaction occurring) Solution quickly fluffed up with fine bubbles; the lower section of solution that was not fluffed was relatively transparent.
Corn leaf Subtle reaction of tiny bubbles slowly rose; solution remained dominantly clear.
Ground meat Solution reacted and created fine, creamy bubbles while lower part remained clear.
Yeast Solution was dominantly clear with tiny bubbles rising rapidly from the bottom.
Potato Subtle reaction of tiny bubbles slowly rose; solution remained dominantly clear.

Table 2.0 – qualitative observation of invertase lab
Sucrose solution being tested Glucose strip test Benedict’s solution
Yeast suspension Light green spots of 100mg/L Light yellow orangish solution that is translucent and milky
Distilled water Light green shades of 100mg/L but are spread out in a smoother manner Negative result: dark greenish brown color

Table 3.0 – qualitative observation of amylase lab
Types of corn seeds Reaction after applying iodine on agar plates
Soaked seeds Plates contained spots of transparent area where soaked corn seeds were place. Overall, there were tiny dots and large patches of dark blackish purple color on agar plate.
Boiled seeds No large patches of dark color, except similar tiny dots that were all over the agar’s surface. There were transparent spots where seeds were placed.
Dry seeds Traces of dark blackish purple color surrounded the areas where corn seeds were placed (transparent). Agar plate was filled with tiny black dots. Agar plate had the darkest shade of color compared to the rest.

Catalase lab
The extracts that were experimented to investigate the enzymatic reaction of catalase on hydrogen peroxide (H2O2) included liver, corn leaf, ground meat, yeast, and potato. All the boiled extracts of these materials yielded no apparent enzymatic reaction when tested with H2O2. This proves how temperature, which is one of the factors that can impact enzymatic reaction, is responsible for chemical reactions not happening. Catalase in these materials were boiled at 100℃, apparently it exceeded each of their optimal temperature. Consequently, catalase within each material was denatured and not able to perform its function properly when tested with H2O2. On the other hand, all the raw extracts reacted to H2O2 at different degrees. Catalase in liver and ground meat extracts caused apparent reactions to H2O2 while catalase in corn lead, yeast, and potato extracts created less apparent enzymatic reaction to H2O2. Their differences in amount of reaction might be explained by various factors such as how pH level in raw meat and liver may be closer to the optimal pH level for catalase to catalyze.

Invertase lab
This lab involves observing effects of adding yeast and distilled water to sucrose solution, which is an example of disaccharide. Despite the poor ability of glucose strips to indicate glucose’s presence, the use of Benedict’s solution allowed more reliable proof of glucose’s presence to be obtained. When added 10 drops of Benedict’s