Enzyme Kinetics of Salivary Amylase

Enzymes are a class of _____ that serve as _____. They help _____ the rate of a reaction, are not _____ by the reaction (so they can be _____), do not change the _____ of the reaction (i.e. the reaction could have happened without the enzyme, just much _____), and lower the _____ of a reaction.

Proteins; biological catalysts; increase; changed; used; nature; slower; activation energy

The first enzymes discovered were given _____ names until an international committee decide to end all enzyme names with the suffix _____. They also decide to make the first part of the name apply to the _____ of the enzyme.

Arbitrary; -ase; function

Oxidation-reduction reactions are catalyzed by _____ enzymes. These include _____, _____, and _____ enzymes

Oxidoreductase; oxidase; dehydrogenase; reductase

Oxidases are responsible for _____.

Transferring electrons from a donor to oxygen

Dehydrogenases are responsible for _____.

Removing hydrogen atoms/electrons

Reductases are responsible for _____.

Gaining electrons

Hydrolysis-dehydration reactions are catalyzed by _____ enzymes. These include _____, _____, _____, and _____.

Hydrolase; peptidases; saccharidases; lipases; dehydratases

Hydrolases are responsible for promoting _____.

Hydrolysis

Peptidases, saccharidases, and lipases are responsible for _____.

Splitting large molecules by adding water

Dehydratases are responsible for _____.

Removing water to make one large molecule from several smaller ones

Reactions involving the transfer of chemical groups are catalyzed by _____ and _____ enzymes. The latter group includes _____, _____, _____, _____, _____, and _____.

Transferase; lyase; kinase; transaminase; phosphorylase; aminase; phosphatase; deaminase

Transferases are responsible for _____.

Exchanging groups between molecules

Kinases are responsible for _____.

Adding or subtracting phosphate groups

Transaminases are responsible for _____.

Adding or subtracting amino groups

Phosphorylases are responsible for _____.

Adding phosphate groups

Phosphatases are responsible for _____.

Subtracting phosphate groups

Aminases are responsible for _____.

Adding amino groups

Deaminases are responsible for _____.

Subtracting amino groups

Isomerases are responsible for _____.

Rearranging atoms

Ligation reactions are catalyzed by _____ enzymes. These include _____ enzymes.

Ligase; synthetase

Synthetases and synthases are responsible for catalyzing _____, i.e. _____.

Dehydration synthesis; joining two substrates using energy from ATP

Activation energy refers to the _____, i.e. the _____, often by _____.

Energy required for the reactants to engage in a reaction; energy required to overcome the repulsion between the electrons of the atoms involved; bringing the substrates close together

Enzymes work by _____ the activation energy needed for a reaction and making them proceed at a _____ rate.

Lowering; faster

Most molecules lack the activation energy needed for a reaction in their natural state. Adding _____ increases the likelihood of a reaction occurring and therefore can increase the _____ of a reaction, but it can also have _____ effects on cells. _____ help reactions occur at _____ temperatures.

Heat; rate; negative; catalysts; lower

Each enzyme has a characteristic _____/_____, with pockets that serve as _____ in the enzyme. The function of an enzyme is dictated by its _____.

3D shape/conformation; active sites; structure

An enzyme’s active site refers to the _____.

Specific region on the enzyme for substrate binding

Enzymes have _____ based on their shape and active site, meaning they can only _____ and catalyze _____.

Specificity; bind to one substrate; one reaction

To function, an enzyme must _____ with reactants known as _____.

Come into contact; substrates

Once a substrate becomes bound to an enzyme, they form a _____, which then breaks down to release products and the enzyme.

Enzyme-substrate complex

T/F: Enzymes can only be used once.

False

The two models for the mechanism of enzyme activity are the _____ and _____ models, with the latter being more likely.

Lock-and-key; induced fit

The lock-and-key model proposes that _____.

Substrates fit into the active site like a key to a lock

The induced-fit model proposes that _____.

Enzymes change their initial fit as the substrate moves into the active site

Salivary amlyase _____ various _____ like _____ and _____, which are _____ of _____.

Hydrolyzes; starches; amylose; amylopectin; polymers; glucose

Salivary amylase begins the digestion of starch by splitting the sugars off of starch in _____ of _____ molecules, which become the _____ (type of sugar) _____ (specific sugar).

Pairs; glucose; disaccharide; maltose

The reaction rate of salivary amylase in the digestion of starch is generally very _____, therefore we must _____ the saliva to _____ the reaction to a rate that we can measure.

Fast; dilute; slow down

At the beginning of the experiment, the control tube should be _____ because _____.

Green; there is iodine present in the tube

At the beginning of the experiment, the reaction tube should be _____ because _____.

Clear; there is no iodine present in the tube

Over time and across the tubes, there should be an obvious _____ in starch concentration and _____ in absorbance.

Decrease; decrease

The change in starch concentration gradually _____ over time, with the most change happening between _____ and _____.

Decreased; Tube 1; Tube 2

The reaction rate _____ over time, as the reaction was fastest at the _____ of the experiment. This is evident by the relatively _____ between the _____ in our figure, indicating that starch concentration decreased at a faster rate in between those tubes. This might occur because there is _____, as the salivary amylase and starch in the reaction tube were in contact for a _____ period of time before coming into contact with the iodine.

Decreased; beginning; steep slope; earlier tubes; progressively less substrate for the enzyme to act on; longer

Variables we did not control for that may have affected the reaction rate include the _____ of the reaction, as this was likely higher in the beginning of the experiment compared to the end. We also did not control for the _____ present in the saliva sample, as this amount differs from person to person and was not directly measured in this experiment.

Temperature; amount of salivary amylase