about enzyme . 急 !! HeLp Me . 20 點 ~

Enzyme is protein and made up of amino acid. The structure of enzyme is hold by different bondings such as hydrogen bond, hydrophoic interaction, di-sulphur linkage and electrostatic bond. The electrostatic bond is due to the prescence of charged part in amino acid. A change in pH, e.g. by adding acid or base, will increase the H-ion or hydroxy ion concecntration in it. So the charged part will become uncharged and interaction between amino acid disappear.This result in unfolding of protein and the enzyme become ineffective.
Temperature change is more or less the same principle but rathan than disrupting the electrostatic bond, temperature will affect all the bond. As temperature increases, the molecules or atoms within the amino acids will gain extra energy and start to vibrate. As soon as the energy of the molecule over the nergy needed to break the down, the bond break and the protein unfold and the specific active site is disrupted. As a result, the enzyme becomes ineffective. Note that decrease in temperature does not denature the enzyme but slow down the activity only.