Properties of enzymes Flashcards
define enzymes
usually soluble proteins which catalyze chemical reactions by lowering the activation energy of these reactoins
Describe enzymes
Accelerate reactions at human body temperatures and at pH conditions found in cells or body compartments
- Bind substrates, form an enzyme-substrate and then an enzyme-product complex, and release the products
- Provide a means for regulating the rate of metabolic pathways depending on the need of the whole body
what are the two names for each enzyme?
- The short recommend name has often the suffix “-ase” and is mainly describing the reaction that is carried out. It can describe the substrates or products which can lead to two correct recommended names
- The systemic name follows a classification thagt includes a name and an Enzyme Commission (EC) number. As a result, there are six major classes and each has numerous subgroups
What is the active site of enzymes?
A relatively small part of a three-dimensional pocket or cleft formed by amino acids that come from different parts of the primary structure
What is the catalytic efficiency of a reaction as opposed to an uncatalyzed reaction?
The catalytic efficiency of enzymes ranges from 10^3-10^8 times faster than uncatalyzed reactions/
What is the specificity of enzymes?
The specificity of enzymes is very high and includes recognition of optical configuration of the substrates. are needed for the breakdown of nutrients in order to generate energy when needed (catabolism)
what are holo and apoenzymes?
Some enzymes need coenzymes/cofactors from vitamins or minerals(holoenzymes)
Apoenzymes are enzymes without the coenzymes
what is anabolism?
allow synthesis and assembly of cellular building blocks
summarize how enzymes work
All reactions: catalyzed or uncatalyzed have to go through a transition state
the enzyme can stabilize the transition state. the active site of the enzyme can provide catalytic groups that favor the formation of the transition state.
Enzymes provide an alternate reaction pathway and as a result, can reduce the energy of activation
Note: Enzymes do not change the Gibbs energy or the delta G of the overall reaction
what is enzyme kinetics?
the study of product formation under specific conditions such as different substrate concentrations, pH, and temperature.
this offers insight into the affinity of the enzyme for different substrates and also for drugs.
The rate of reaction is product formation over time expressed as the actual amount in g.
The velocity of reaction
What is the velocity of a reaction?
The velocity is product formation over time expressed in concentrations and is used in Biochemistry.
What is the effect of substrate concentration on the velocity?
The velocity increases at higher substrate concentration for any enzymatic catalyzed reaction until Vmax is reached
At Vmax all available binding sites on the enzyme are saturated with substrate and the product formation cannot be increased any further.
what is the effect of temperature on the velocity?
The velocity increases with hgiher temperature except when the temperature rises above 40 degrees celcius. This causes the human enzymes to be denatured
Thermophilic bacteria found in hot springs have theior optimal velocity at higher temperatures at 70 degrees. Their purified enzymes are used for experiments
What is the effect of pH on velocity?
A. The concentration of hydrogen ions affects the reaction velocity. The enzyme and substrate have chemical groups that need to be either ionized or unionized in order to interact.
B. An extreme pH can denature the enzyme
C. Different enzymes can have different optimal pH. Examples of enzymes that function at different pH’s in the human body
what is the function of Pepsin?
Cleaves dietary proteins and acts in the lumen of the stomach under acidic conditions
