BIO NMDCAT

Low temperatures slow molecular motion without permanently altering enzyme structure. Normal activity usually returns when the temperature is restored to the optimum value.

Heat primarily disrupts weak interactions such as hydrogen bonds, altering the shape of the active site and reducing enzyme activity.

Correct protonation of amino acid side chains is essential for substrate binding and catalysis. Extreme pH alters these charges.

Pepsin functions optimally around pH 2 due to the highly acidic conditions of the stomach.

Trypsin is adapted to the alkaline environment of the small intestine, where its catalytic residues remain correctly ionized.

Constant pH allows accurate measurement of other variables by preventing changes in the enzyme's active site charge.

If substrate is insufficient, additional enzyme molecules remain unused because there are not enough substrate molecules to occupy their active sites.

High temperatures disrupt hydrogen bonds and other weak interactions, causing loss of the enzyme's three-dimensional structure and decreasing catalytic activity.

At saturation, all enzyme molecules are engaged in enzyme-substrate complexes, so increasing substrate concentration no longer increases the reaction rate.

At low substrate concentrations, many active sites remain free. Therefore, increasing substrate concentration proportionally increases enzyme-substrate complex formation.

Enzymes from different organisms and tissues have different amino acid compositions and structures, resulting in different optimum temperatures.

Each enzyme has a unique active site with specific amino acid residues that require particular ionization states for maximum catalytic efficiency.

Increasing both enzyme and substrate together provides more catalytic sites and sufficient substrate, leading to a marked increase in reaction rate until another factor becomes limiting.

At low substrate concentrations, many enzyme active sites are unoccupied. Increasing substrate concentration increases the frequency of enzyme-substrate complex formation and accelerates the reaction.

Maximum velocity (Vmax) is reached when every active site is occupied. Adding more substrate cannot further increase the reaction rate.

With substrate in excess, the reaction rate depends mainly on the number of enzyme molecules available to catalyze the reaction.

Once every enzyme molecule has formed an enzyme-substrate complex, the enzyme becomes saturated. The reaction reaches Vmax, and additional substrate cannot further increase the rate.

Changes in pH alter the charge of amino acid side chains, affecting substrate binding and catalytic activity without changing the enzyme's molecular mass.

With excess substrate, every added enzyme molecule finds substrate to act upon, causing the reaction rate to increase proportionally.