B.3 Factors Affecting the Activity of Enzymes

Apoenzyme

The protein part of an enzyme, which requires cofactors for its enzymatic activity.

activated E-S complex

The activated complex formed when an enzyme binds to its substrate.

Optimum temperature

where the enzyme and its substrate have the best shape to combine and form an E-S complex.

Denaturation

The process in which an enzyme loses its tertiary structure due to extreme temperature or pH, resulting in loss of function.

Hyperthermia

A condition where body temperature exceeds 40°C, leading to severe impairments in enzyme function.

pH

A measure of acidity or alkalinity, affecting enzyme stability and activity.

Buffers

Substances that help maintain stable pH levels in biological systems. Bicarbonate ions.

Competitive inhibitors

Substances that compete with substrates for the active sites of enzymes, and also have similar shapes to the substrates.

Allosteric inhibitors / noncompetitive inhibitors

Inhibitors that bind to an enzyme at a site other than the active site, causing a change in enzyme shape and function. This affects the electron distributions in the enzymes.

Kinetic energy

The energy of motion, which influences the movement of molecules and reaction rates.

Substrate concentration

The amount of substrate present, which affects the rate of enzymatic reactions.

Induced Fit Hypothesis

The theory that an enzyme changes shape to better fit the substrate upon binding.

Hypothermia

A condition occurring when body temperature falls below 35°C, leading to decreased enzyme activity.

Pepsin

A digestive enzyme that works best at a highly acidic pH of about 2.5 in the stomach.

Enzymatic activity

The rate at which enzymes catalyze reactions, influenced by factors like temperature, pH, and substrate concentration.

Heavy metal ions

Toxic elements that disrupt enzyme function by distorting enzyme shape.

H-bonds

are weak and sensitive to temperature, bonds break if temperature is too high, or loses structure.

Homeostatic responses of hyperthermia

increased delivery of blood to the surface, and sweating.

Body reaction to hypothermia

shiver, which generate a little heat ; form goosebumps, and deliver less blood to the surfaces.

optimum pH

7.35

large positively charged nuclei, giving them high affinities or attractive powers towards electrons. they tend to draw other molecules electrons to themselves.

heavy metal ions