ENZYME – BIOLOGICAL CATALYST (PART II)

Objectives for todayMode of actions of enzymesNaming of enzymesSpecificity of enzymes

Overview Biological Molecules

Water and Living Organisms

Carbohydrates, Fats and Proteins

Enzymes

Lock & Key hypothesis

Mode of Action

Factors affecting enzyme

reactionsSpeed up chemicalRxnNot chemically altered at the endOf Rxn

Lowering Activation Energy

Specificity

Temperature pH

RecapEnzymes are biological catalysts found in both plants and animals.

Catalysts are….?

Cut the wire

ScissorsSpeed up the cutting

process!

After cutting, still remain as a

scissors! Not altered!

Enzyme as biological catalyst

ENZYMESpeed up the

chemical reaction! Like condensation and hydrolysis

Not chemically altered at the end of

the reaction!

3. Lower Activation energy

Reactants = “ You in bed in

home clothes”

6:20am

Products = “ You in school with uniform”

7:29am

Normal Day

Exam!

3. Lower Activation energy

Reactants = “ Starch + Water”

Products = “Glucose

molecules”

Without Enzyme

s

With Enzyme

s!

Demonstration on the breakdown of starch by enzyme (amylase)

Saliva contain amylase, an enzyme that breaks complex carbohydrates (starches) into simple sugar (glucose)

“Now that we know enzymes are catalysts, and roughly know its shape, but we still do not know how the enzymes interact with the reactants!”

How does an enzyme really works?

Mode of actions in 3D view!

Mode of action1. Enzymes reaction depends on the

availability of active sites2. Active sites are depression or “pockets” on

the surface of an enzyme molecule into which substrate molecule can fit.

3. The substrates binds to the enzyme, forming an enzyme-substrate complex

4. Reactions takes place at the active sites to convert the substrate molecules into product molecules

5. The products separates, leaving the enzyme unaltered and free to combine again with more substrate molecules.

2D view of enzyme in action

5

Activity time!Using plasticine to model

enzymes mode of actions!Split into 4 groupsEach group take a set of

plasticineMake your

own enzyme!

ObjectivesMake your own enzymes that fits

the substrates given to youTime limit is 5minsAfter making, each group is

supposed to describe the mode of actions of enzymes.

Enzymes are specific

Specificity of enzymes explained by the Lock and Key hypothesisOne key only fits one lock! Inside the lock, it has a specific

shape that only takes in the correct key with the correct complimentary shape.

Enzymes are specific◦Each chemical reaction is catalysed

by a unique enzyme◦A substrates fits into an enzyme’s

activity site in a way similar to how a key fits into a lock.

◦Lock and Key hypothesis

How do we name our enzymes?

How do Canberra name their classes?3E1All the sec 3 classes start with the

number 3Follow by E, N or TThis allows people to quickly

recognize the classes. So, how can we name enzymes so

that people can recognize that the names given actually belongs to the enzymes and not something else?

Name that Enzyme !!!

I. Name that Enzyme !!!

Proteinase Substrate Name +

-ase

EnzymeS

Name That Enzyme

I. Name that Enzyme !!!

Lipidase

Carbohydratease

I. Name that Enzyme !!!

Enzyme Nomenclature and Classification:

Enzymes are commonly named by adding a suffix "-ase" to the root name of the substrate molecule it is acting upon. For example,

Lipase catalyzes the hydrolysis of a lipid triglyceride into fatty acids and glycerol.

Sucrase catalyzes the hydrolysis of sucrose into glucose and fructose.

A few enzymes discovered before this naming system was devised are known by common names.

Examples are pepsin, trypsin, and chymotrypsin which catalyzes the hydrolysis of proteins.

Quick facts

Any Questions?

SummaryEnzymes

Characteristics

Specific

Speed up Chemical

Rxn

Lower activation

energy

Remains unaltered

Requires in minute amount

Mode of action

Lock and key hypothesis

Induced fit hypothesis

Video on enzymes

HW- Due Next Tue 31st MarchGo to the biology blog

canberra3E1.wordpress.com and do a short online quiz. Participation marks will be given.

Watch a video posted on the web and State some common uses of enzymes in

our societyScientist can create ‘super enzymes’ that

can break down bio molecules very fast and efficient. Do you think it is safe to mass produce this and use it in our society?

Review questions1) Are Enzymes: 

                            A - Carbohydrates                              B - Protiens                              C - Nucleic Acids                              D - Lipids                              E - Other 

Going a bit furtherG6PD, a functional enzyme gone

missing in in the body!Cannot break down Glucoe-6-

Phosphate, which will be accumulated in the cells.

And it disrupts many other chemical reaction in the body

G6PD enzyme

Next lessonFactors affecting enzymatic

reactions