Enzymes have high catalytic efficiency

Enzyme-catalyzed reactions require mild reaction conditions

Generally, conditions that denature biological macromolecules can cause enzymes to lose their catalytic activity.

Enzyme activity can be adjusted by controlling environmental conditions to adjust the reaction rate

structural specificity

Stereospecificity

Oxidoreductases, transferases, hydrolases, polymerases Class, isomerase, synthase, isozyme

pure protein

conjugated protein

monomeric enzyme

Oligomerase

multienzyme complex

The Km value is a characteristic constant of an enzyme and is only related to the nature of the enzyme and the substrate catalyzed by the enzyme. It is related to the conditions of the enzymatic reaction and has nothing to do with the concentration of the enzyme.

The substrate with the smallest Km is called the optimal substrate or natural substrate

The larger the Km value, the smaller the affinity between the enzyme and the substrate.

Any substance that can reduce the catalytic activity of an enzyme without causing denaturation of the enzyme protein

irreversible inhibitor

Reversible inhibitor

After the regulator is combined with the regulatory site of the enzyme molecule through non-covalent bonds, Causes changes in the conformation of the enzyme and thereby changes the active state of the enzyme, which has An enzyme with allosteric regulation

positive synergy

negative synergy

Features

[S] changes little, V changes big

As regulatory enzymes in metabolic pathways

catalyze the same chemical reaction, and the molecular structure of the enzyme protein, A group of enzymes with different physical and chemical properties and even immunological properties

Different genes produce different proteins

Monomeric enzyme, oligomeric enzyme

Chemical modification of enzymes is another way of rapid regulation in the body

Enzymes exist in two differently modified and differently active forms

There are changes in covalent bonds

Influenced by other regulatory factors such as hormones

Generally an energy-consuming process

There is an amplification effect

The region of an enzyme molecule that directly binds to a substrate and catalyzes a chemical reaction with the substrate to produce a product.

binding group

catalytic group

The active center only accounts for a small part of the enzyme molecule volume (1%-2%)

The active center is a crack in the three-dimensional structure

The conformation of the enzyme active center and the conformation of the substrate are not necessarily complementary. Only when the enzyme binds to its substrate does its conformation occur changes so that the two complement each other

The active center is located in the clefts (pits, holes) on the enzyme surface. which is equivalent to a hydrophobic environment

The substrate binds to the active center of the enzyme through secondary bonds

The conformation of the active center is mobile

Three Points of Attachment Theory

lock and key theory

induced fit theory

transition state complementarity theory

nucleophilic catalysis

electrophilic catalysis

The imidazole group of histamine is the most active functional group. Donate and accept protons very quickly

The hydrophobic environment is conducive to enzyme catalysis, Helps reduce reaction activation energy