CC2 LEC - ENZYMOLOGY

• ENZYMOLOGY

  • It is a branch of science that deals with the study of physical and chemical properties of enzymes, its functions and clinical applications.
• Enzymes

  • Refers to proteins that catalyze biochemical reactions.
  • These are proteins that are produced within the cell to catalyze or hasten the chemical reaction of organic matter. It is composed of organic substances that contain carbon.
• In the reaction, the enzyme is only after the velocity of the reaction. ○ However, in the process, it is not consumed nor altered in composition.
• It is an intracellular protein in nature and is found within the cell. Therefore, enzymes are not normally found or high in the plasma or serum. ○ In the plasma/serum ■ It has a normally low enzyme level since enzymes are normally found in the cell. ○ Elevated level of enzymes (plasma or serum) ■ Can be associated with a clinical state, diseases, or abnormality.
• Hydration of Carbon Dioxide (Respiration Process) ● When carbon dioxide is hydrated in the lungs, gas exchange happens which is catalyzed by the enzyme.
• Nerve Induction ● It is through the catalytic action of an enzyme that nerve impulse transmission is accelerated when the enzyme is present.
• Muscle Contraction ● When muscle contracts, it forms: ○ Movement and Heat generation ● This forms whenever an enzyme is present through the catalytic action.
• Nutrient Degradation ● Gastric fluid in the intestinal secretions is rich in enzymes with the following functions: ○ Breakdown, Degradation, Digestion, and Absorption of macromolecules
• Growth and Reproduction ● Enzymes support the activity of hormones and other biomolecules.
• Energy Storage and Use ● Energy can be stored in the skeletal muscle and is consumed when needed through the catalytic action of enzymes.
• ACTIVE SITE ● It is a waterless cavity of an enzyme where substrates bind and undergo chemical reaction.
• Substrate and binding sites are always specific. The shape of the substrate must fit into the cavity so that binding will occur. ○ If the configuration of the active site does not match the substrate, there would be no binding.
• LOCK AND KEY CONCEPT ● Lock = Active Site || Key = Substrate Note: ACTIVE SITE = SUBSTRATE BINDING
• ALLOSTERIC SITE ● It is a waterless cavity other than the active site that binds with the regulatory or effector molecule.
• Substrates

  ● It is specific for a particular enzyme. ● It refers to substances acted upon by enzymes, usually has 3 letters “-ase” at the end.
• Cofactors

  ● These are non-protein entities or substances that when added in the enzyme substrate complex can enhance and manifest enzyme activity.
• Coenzymes ● An organic cofactors that serves as the second substrate. When coenzymes are added in the enzyme-substrate complex, it enhances enzyme activity.
• Nicotinamide Adenine Dinucleotide (NAD) Nicotinamide Adenine Dinucleotide Phosphate (NADP)
• NAD – Oxidized, Low absorbance at 340 nm.

  NADP – Reduced, High absorbance 340 nm
• Activator

  ● These are either metallic or non-metallic ions that enhance the spatial configuration of the active site for substrate binding.
• Metallic: Calcium, Magnesium, Iron and Zinc

  Non-Metallic: Chloride and Bromide
• Isoenzymes

  ● These are enzymes that are with similar enzymatic activity but differ in the physical, biochemical, and immunologic properties.
• Physical Property

  – Classification of electrophoretic mobility of isoenzymes or properties of enzymes in electrophoresis.
• Apoenzymes

  ● Protein portion of an enzyme when subjected to denaturation where it can lose its catalytic activity.
• Tertiary Structure – structural and functional structure of protein that is affected when there is denaturation process.
• Holoenzymes

  ● An active substance that is formed from the combination of a coenzyme and apoenzyme.
• When coenzymes are tightly bound to apoenzymes they are called the prosthetic group.
• International Union of Biochemistry (IUB)

  • International body that is responsible for naming enzymes.
• Systematic Name

  • Defines the substrate acted, reaction catalyzed and possibly the co-enzyme involved.
  • It is the Long Name
• Recommend ed Name

  • Trivial or Usable Name of the enzyme. Usually, the name used by physicians for laboratory testing.
• Enzyme Commission (EC) Numerical Code

  ● Enzyme Commission, composed of 4 digits.
• 1 st Digit – Enzyme classification
• 2 nd Digit – Sub-classification
• 3 rd Digit – Enzyme sub-sub classification
• 4 th digit – Serial number, specific to enzyme sub-sub classification.
• 1. Oxireductases
  2. Transferases
  3. Hydrolases
  4. Lyases
  5. Isomerases
  6. Ligases
• Oxidoreductases ● These are enzymes that catalyze the redox reaction between two substrates.
• Redox Reaction: Transfer of electrons or hydrogen ions from one substrate to another.
• Oxidoreductases: A - + B → A + B
• Transferases

  ● These are enzymes that catalyze the transfer of chemical groups whether it is phosphate, methyl group etc. other than hydrogen ion from substrate to another