BIOCHEMISTRY LECTURE / FIRST SEMESTER
ENZYMES
LEARNING OBJECTIVES
ENZYME PARTS
I. Define enzyme The activity of an enzyme depends, at the minimum, on a
II. Know the differences among absolute specific protein chain. In many cases, the enzyme
specificity, relative specificity and stereospecify consists of the protein and a combination of one or more
III. Explain the mechanism of enzyme action parts called cofactors. This enzyme complex is usually
simply referred to as the enzyme.
IV. Determine the different factors that affect the
Apoenzyme: The polypeptide or protein part of the
rate of enzyme reaction enzyme is called the apoenzyme and may be inactive in
V. Distinguish between reversible and irreversible its original synthesized structure. The inactive form of the
inhibitors apoenzyme is known as a proenzyme or zymogen. The
proenzyme may contain several extra amino acids in the
protein which are removed, and allows the final specific
WHAT ARE ENZYMES? tertiary structure to be formed before it is activated as an
Enzymes are catalysts apoenzyme.
Catalysts are substances that speed up chemical Cofactors: A cofactor is a non-protein substance which
reactions may be organic, and called a coenzyme.
Reactions with enzymes are up to 10 billion times faster
than those without enzymes. NOMENLACTURE OF ENZYMES
Enzymes are specific for one particular reaction or group
1. Trivial System
of related reactions.
– based on the substrate of the enzyme and the type of
Many reactions cannot occur without the correct enzyme
present. reaction catalyzed
Use of ase ending
GENERAL CHARACTERISTICS OF ENZYMES 2. International Enzyme Commission
The catalytic behavior of proteins acting as enzymes is one – Groups enzymes into six classes
of the most important functions that they perform in living
cells. MAIN ENZYME CLASSES in the
Enzymes are well-suited to their roles in three major ways: IUBMBEC System
- They have enormous catalytic power
- They are highly specific in the reactions they catalyze
- Their activity as catalysts can be regulated
Just like any chemical catalysts, what an enzyme does is to lower
the activation energy (Ea). Activation energy is the energy needed
to cause an effective collision and allow a reaction to proceed
forward. The energy profile of a reaction is shown below.
• All chemical reactions require an initial input of energy called
activation energy
– the activation energy initiates a chemical reaction by
destabilizing existing chemical bonds
• Reactions become more likely to happen if their activation
energy is lowered – this process is called catalysis – catalyzed SOPHIA NICOLE POSERIO MACAM
reactions proceed much faster than noncatalyzed reactions UNIVERSIDAD DE MANILA
BSN- 14
ENZYMES
LEARNING OBJECTIVES
ENZYME PARTS
I. Define enzyme The activity of an enzyme depends, at the minimum, on a
II. Know the differences among absolute specific protein chain. In many cases, the enzyme
specificity, relative specificity and stereospecify consists of the protein and a combination of one or more
III. Explain the mechanism of enzyme action parts called cofactors. This enzyme complex is usually
simply referred to as the enzyme.
IV. Determine the different factors that affect the
Apoenzyme: The polypeptide or protein part of the
rate of enzyme reaction enzyme is called the apoenzyme and may be inactive in
V. Distinguish between reversible and irreversible its original synthesized structure. The inactive form of the
inhibitors apoenzyme is known as a proenzyme or zymogen. The
proenzyme may contain several extra amino acids in the
protein which are removed, and allows the final specific
WHAT ARE ENZYMES? tertiary structure to be formed before it is activated as an
Enzymes are catalysts apoenzyme.
Catalysts are substances that speed up chemical Cofactors: A cofactor is a non-protein substance which
reactions may be organic, and called a coenzyme.
Reactions with enzymes are up to 10 billion times faster
than those without enzymes. NOMENLACTURE OF ENZYMES
Enzymes are specific for one particular reaction or group
1. Trivial System
of related reactions.
– based on the substrate of the enzyme and the type of
Many reactions cannot occur without the correct enzyme
present. reaction catalyzed
Use of ase ending
GENERAL CHARACTERISTICS OF ENZYMES 2. International Enzyme Commission
The catalytic behavior of proteins acting as enzymes is one – Groups enzymes into six classes
of the most important functions that they perform in living
cells. MAIN ENZYME CLASSES in the
Enzymes are well-suited to their roles in three major ways: IUBMBEC System
- They have enormous catalytic power
- They are highly specific in the reactions they catalyze
- Their activity as catalysts can be regulated
Just like any chemical catalysts, what an enzyme does is to lower
the activation energy (Ea). Activation energy is the energy needed
to cause an effective collision and allow a reaction to proceed
forward. The energy profile of a reaction is shown below.
• All chemical reactions require an initial input of energy called
activation energy
– the activation energy initiates a chemical reaction by
destabilizing existing chemical bonds
• Reactions become more likely to happen if their activation
energy is lowered – this process is called catalysis – catalyzed SOPHIA NICOLE POSERIO MACAM
reactions proceed much faster than noncatalyzed reactions UNIVERSIDAD DE MANILA
BSN- 14
