ENZYMES::PART 6

Applications of enzymes

-           Used in wine production.

-          Making cheese (rennin).

-          Candy production (invertase).

                              

-          Bread whitening (lipoxygenase).

-          Meat tenderization (papain and ficin).

                                  

ENZYMES ::PART 5

Enzyme reaction rates

-          Enzymes bind to substrates and convert them into products.

-          Most of the enzymes are produced in an inactive form called
        zymogen, these zymogen are acted upon by molecules that
        reactivate the enzyme.

-          The velocity of the enzyme catalysed reaction depends upon
        the substrate concentration.

                                                         

-          But at a certain level the enzyme is completely saturated with
        substrate so the velocity reaches a maximum point and don’t
        increase with further addition of substrate.

ENZYMES:: PART 4

Specificity of enzymes

-          Enzyme binds only to its substrate.

-          Enzymes have highly specific structure.

                                                        

-          Enzymes are specific towards cis and trans forms of substrate.

-          Enzymes are very sensitive towards temperature, pressure and
        pH.

ENZYMES:: PART 3

Fischer’s lock and key model

-          Enzyme substrate union depends upon the reciprocal fit          
       between the structure of enzyme and the structure of the
       substrate.

                                           

-          The substrate and active site of enzyme fit each other more or
        less like a lock and key.

-          The enzyme substrate union results in the release of energy.

-          The energy released helps the substrate molecule to attain
        activation energy.

                                   

-          In the activated state certain bonds of the enzyme-substrate
        complex become susceptible to cleavage.

-          This cleavage produces product and the enzyme remains
        unchanged.

ENZYMES::PART 2

Types of enzymes (based on site of action)

-          Endozymes: -

o   Produced in the cell.

o   Site of action is inside the cell itself.

o   Ex: - DNA polymerase.

-          Exozymes: -

o   Produced inside the cell.

o   Site of action is outside the cell.

o   Ex: - adrenaline.

ENZYMES:: PART 1

INTRODUCTION

-          The term enzyme was given by Wilhelm Kuhne to bio catalysts.

-          Major group of proteins are enzymes that are biocatalysts.

-          All enzymes are proteins, but all proteins are not enzymes.

-          Without enzymes no biological reaction would be possible.

-          Enzymes don’t alter chemical equilibrium.

-          All enzymes have word “ase” as their postfix.

-          Enzymes speed up biological reactions.

-          Example: - Carbonic anhydrase is an enzyme that enhances the dissolution rate of CO2 in water by 10^8 times.

                                            

-          Enzymes have an active site where substrate molecules attach. 

NUCLEIC ACIDS:: PART 7

Types of DNA

-          A-DNA

o   Right handed orientation.

o   Found in conditions with low humidity

-          B-DNA

o   Right handed orientation

o   Most dominant form in almost all organisms.

                                 

-          Z-DNA

o   Left handed orientation.

o    Its sugar backbones are zigzag in appearance.

NUCLEIC ACIDS:: PART 6

Structure of DNA by Watson and Crick

-          The 3D model of DNA was given by James.D.watson and Fransis.H.crick in 1953.

                                              

-          They said that the DNA is double stranded.

-          The two strands were antiparallel one ran from 5’ to 3’ direction and the other ran from 3’ to 5’ direction.

                                        

-          Adenine formed double bonded hydrogen bond with thymine and guanine formed triple bonded hydrogen bond with cytosine.

-          The two strands of a DNA can be represented as a step ladder folded along its imaginary axis to form a “Double Helix”.