2.5 Syllabus
U1. Enzymes have an active site to which specific substrates bind
-Enzyme: Globular proteins that works as catalysts → Speed up chemical reactions without being altered themselves
=Biological Catalysts
=Substance that enzymes convert into products in these reactions are called substrates.
-Enzymes only catalyze one biochemical reaction and thousands of reactions take place in cells, almost all of them needs to be catalyzed.
→Enzyme-substrate specificity
→Big difference between biochemical catalysts & non-biochemical catalysts (metal)
2. Shape and chemical properties of the active site and the substrate match each other
→ Substrate bind, not other substances. Forms enzyme-substrate complex.
3. Substrate converted into products while they are bound to the active site and products are then released
→ Freeing the active site to catalyze another reaction
=Biological Catalysts
=Substance that enzymes convert into products in these reactions are called substrates.
-Enzymes only catalyze one biochemical reaction and thousands of reactions take place in cells, almost all of them needs to be catalyzed.
→Enzyme-substrate specificity
→Big difference between biochemical catalysts & non-biochemical catalysts (metal)
- Speeding up reactions
2. Shape and chemical properties of the active site and the substrate match each other
→ Substrate bind, not other substances. Forms enzyme-substrate complex.
3. Substrate converted into products while they are bound to the active site and products are then released
→ Freeing the active site to catalyze another reaction
U2. Enzyme catalysts involves molecular motion and the collision of substrates with the active site
- Three stages
2. Substances are bound to the active site, they change into different chemical
3. Products separate from the active site, leaving it vacant for substrates to bind again.
- The substrate molecule can only bind to the active site if it moves very close to it
- Collision: Substrate molecule comes together to active site
→Both substrate and enzyme are freely moving
→Substrates are usually smaller than enzymes = moves faster
→When they collide = Successful collusion, causing it to work
U3. Temperature, pH and substrate concentration affect the rate of activity
1. Temperature
→When heated, particles are given more kinetic energy. Enzyme + substrates will move around faster at higher temperature of chance of a substrate molecule colliding with active site of the enzymes is increased → increased enzyme activity.
→When heated at high temperature, enzyme vibrate and chance of bonds breaking is increased. Bond break → enzyme change structures with active site.
2. pH
→ Lower pH = Acidic = More presence of hydrogen ions
→ Higher pH = Alkaline
- Most enzymes have optimum pH => Activity is highest
-If pH changed from optimum = Enzyme activity decreases then eventually stops.
-Enzymes do not have same pH optimum -> Very dependent on the environment n which enzymes work
3. Concentration
-When on enzymes is bound, it cannot bind until it has lost the original one.
→Active site occupied
-When substrate concentration increases, enzymes can bind very quickly with it as there are many → Rate increases
-If there're too many, no more effect, as enzymes can can do that to much work
→When heated, particles are given more kinetic energy. Enzyme + substrates will move around faster at higher temperature of chance of a substrate molecule colliding with active site of the enzymes is increased → increased enzyme activity.
→When heated at high temperature, enzyme vibrate and chance of bonds breaking is increased. Bond break → enzyme change structures with active site.
2. pH
→ Lower pH = Acidic = More presence of hydrogen ions
→ Higher pH = Alkaline
- Most enzymes have optimum pH => Activity is highest
-If pH changed from optimum = Enzyme activity decreases then eventually stops.
-Enzymes do not have same pH optimum -> Very dependent on the environment n which enzymes work
3. Concentration
- Enzymes cannot catalyze reactions until the substrate binds to active site.
-When on enzymes is bound, it cannot bind until it has lost the original one.
→Active site occupied
-When substrate concentration increases, enzymes can bind very quickly with it as there are many → Rate increases
-If there're too many, no more effect, as enzymes can can do that to much work
U4. Enzymes can be denatured
-Enzymes are globular protein and like other proteins, their structure can be irreversibly altered by certain conditions
=> Denaturation of enzyme caused by pH or temperature
-Denatured enzyme = active site is altered, so the substrate can no longer bind
→ If it binds, catalyze does not occur
→ In many cases, denatured enzymes become insoluble in water and form a precipitate
=> Denaturation of enzyme caused by pH or temperature
-Denatured enzyme = active site is altered, so the substrate can no longer bind
→ If it binds, catalyze does not occur
→ In many cases, denatured enzymes become insoluble in water and form a precipitate
U5. Immobilized enzymes are widely used in industry
-Immobilized=Attached to another material, so the movement is restricted
ex) Attaching enzymes to a glass surface, trapping the in an alginate gel.
2. Enzyme will not be washed away = Recycled
3. Enzymes more long-lasting = Protected by the one connected ones, so they won't need to be replaced constantly
4. Substrates can be exposed to higher enzyme concentration
ex) Attaching enzymes to a glass surface, trapping the in an alginate gel.
- Advantages of enzyme immobilization
2. Enzyme will not be washed away = Recycled
3. Enzymes more long-lasting = Protected by the one connected ones, so they won't need to be replaced constantly
4. Substrates can be exposed to higher enzyme concentration
A1. Methods of production of Lactose-free milk and its advantages
- Some people lactose intolerant
→Cannot digest milk or sugar
→Lactose passes on to their large intestines without being hydrolyzed to its constituent monosaccharides
→Bacteria feeds on lactose → provides fatty acids and methane, causing diarrhea.
Lactose --- Lactase → Glucose + Galactose