Enzymes are proteins that act as catalysts and have a unique shape that allows them to bind to specific substrates. They remain unchanged at the end of reactions and can be reused. Enzymes are named based on their substrates and have optimal temperatures and pH levels for activity. Coenzymes assist enzymes during reactions. Enzyme activity increases with temperature until they are denatured above 50°C and is also affected by pH levels. During seed germination, water activates enzymes like amylase and protease that digest starches and proteins into sugars and amino acids to fuel growth of the plumule and radical.

1. ENZYMES
B M Subramanya Swamy M.Sc. B.Ed.
CIE Co ordinator & Examination Officer
Kanaan Global School
Jakarta
Indonesia
swamy@kanaanglobal.sch.id

2. Enzymes
• Introduction
• Mode of function
• Coenzymes
• Uses of enzymes
• Enzyme activity
• Enzymes in seed germination

3. Introduction
• Enzymes are proteins that function as biocatalyst
• It has a unique shape that acts on specific
substrates like a lock and key
• Enzymes are produced in minute quantities by living
cells
• It can be used over and over again as it remain
unchanged at the end of reaction
• Enzymes are named by adding suffix ase to the
name of its substrate
E.g. sucrase acts on sucrose

4. Mode of action Inactivation (by changing the active site)
Very specific in their substrate Heat (usually above 50 C)
Binds to substrate on the active site pH changes
Bonds are temporary By position
Anabolic : produce complex molecules from
simple molecules
Catabolic : split large molecules into smaller
ones
Heavy metals such as lead,arsenic,mercury

5. Mode of action of enzymes

6. Coenzymes
• Non protein molecules e.g. vitamin B
• Joins enzymes temporarily during a reaction
• Remains unchanged at the end of a reaction
• Without the coenzyme, these reaction will not
occur
E.g. lack of vitamin B leads to a stunted growth
paralysis and loss of appetite

7. Uses of enzymes
Enzymes Usage type Effects
Protease Industrial use Skinning fish , removing hair
Amylase Industrial use Production of chocolate, syrup
Cellulase Industrial use Softening vegetable, removing seed coats
Protease Everyday Added to washing powder to remove protein stains
Lipase Digestion Converts fats to fatty acids and glycerol
Amylase Digestion Converts starch to glucose

8. Enzyme activity
Temperature pH
Increase in temperature increases the activity -------------------------------------------------------------
Increase 10 C leads to the activity doubling Specific pH for every enzymes
Optimal temperature around 45 C Work best at optimal pH
Temperature above 50 C will denature the
enzyme
Changes in acidity and alkalinity will denature
the enzymes
Temperature damage not reversible Damage is reversible by changing pH

10. Seed germination
• Seed germination takes place in the presence
of water oxygen and a suitable temperature
• During germination water enters the seed
causing the seed to swell rupturing the testa
• Water serves to soften the testa making it
more permeable to oxygen and carbon di
oxide
• Water enters the cotyledon's activates the
secretion of enzymes to digest the insoluble
starch and protein present in the cotyledons

11. • E.g. amylase to convert starch to glucose
Protease to convert protein to amino acids
• These products of digestion are send to the
plumule and radical for growth
• Glucose is used during respiration to provide
energy for cell growth
• Amino acids are used in the formation of new cell
proteins