Regulation of the molecular structure of enzymes.

are often inhibited or excited by metabolites, most of which are achieved through metastases. Therefore, the vitality of these enzymes can be very sensitively regulated by the concentration of metabolites, which is of great significance to the body's own metabolic regulation.

, variant enzymes are important for regulating the body's energy metabolism. In the rest state, the body energy consumption is reduced, ATP accumulates in the cell, and ATP is the inhibitor of fructose fructose kinase phosphate, so it leads to the accumulation of F-6-P and G-6-P, G-6-P is also the inhibitor of glycase, thereby reducing the oxidation and decomposition of glucose.

addition, ATP is also an inhibitor of acetone kinase and citric acid synthase, which strengthens the inhibition of glucose oxidation and decomposition, thereby reducing the further production of ATP. Conversely, when ATP decreases in the body and ADP or AMP increases, AMP can inhibit fructose 1,6-disphosphatase, reduce glycosin isogeneity, and activate enzymes such as fructose kinase phosphate and citric acid synthase to accelerate the decomposition and oxidation of sugar, which is good for the production of ATP in the body.

, through the configuration adjustment, so that the body's ATP generation will not be too much or too little, to ensure that the body's energy is used effectively.

mechanism of variable structure regulation is known at present, and enzymes that can be regulated by variant are often polymers consisting of more than two sub-base. Some sub-base and actuation binding, catalytic action, called catalytic sub-base, and some sub-base and substructive agent combination, play a regulatory role, called regulation sub-base. However, it is also available on the same sub-base both catalytic and regulatory parts.

is the binding of non-co-priced bonds between the mutant and the regulation sub-base (or site), which changes the composition of the enzyme (e.g., becomes loose or tight), thereby inhibiting or activating the enzyme activity. Unlike Mi-Man's enzymes, the kinetics do not conform to the Miman equation: the relationship curve between the speed of the enzymatic reaction and the concentration of the actogenes is not rectangular but often S-shaped, and the S-shaped curve is similar to the dissocent curve of hemoglobin hemoglobin (Figure 9-1).

what effect does the variant have on the composition of enzyme molecules when the variant is combined with the regulated sub-base (or site)? The process is described as an example of fruit-1,6-phosphatase. Fructose-1,6-phosphatase is made up of four sub-base with the same structure, each with a molecular weight of approximately 310,000Da.

there are both catalytic and regulatory parts on each sub-base. A molecule FDP can be combined on the catalytic site and a molecular structure changer can be combined on the regulatory site. There are two forms of this enzyme, namely tight type (T type, high activity) and relaxation type (R type, low activity). AMP is the inhibitor of this enzyme.

when the enzyme is in T-type, it is difficult to bind to AMP because the regulating part is transferred to the polymer, so it is insensitive to AMP and shows high activity. After the first AMP molecule is combined with the regulating site, the T-type is gradually transformed into R-type, the sub-substations are changed one after another, the adjustment site is exposed one after another, the affinity with AMP is gradually increased, the activity of the enzyme gradually decreases, which is fructose-1,6-dphosphatase from tight type to relaxation-type alteration process.

inhibitors promote the transition from highly active to low-active, and activation of variants promotes the transition from low-active to highly active. This process of composition is reversible.

: Catalytic site X: FDP on the enzyme sub-base of the regulatory site FDP: fructose-1,6-diphosphate

destructor can be the base of the enzyme, can also be the final product of the enzyme system, and there are otherAn enzyme can have a variety of variant effect agents present.

of fructose-1,6-phosphatase is a reversible change of T-type and R-type. The metastatic effects of some enzymes can also be manifested in the polymerization or dissocation of enzyme molecules, such as acetylCoA pyrethase, which is a key enzyme in the synthesis of fatty acids.

it is a primary polymer made up of four different sub-base, each with different functions: biotin carrier protein, which binds to co-based biotin<; "> transferase, which transfers the carboxyl on the biotin to acetylCoA to form acetylCoA, and regulates the sub-base, which binds to citric acid or isocric acid to polymerization of the primary polymer.

Kieinschmidt and others have seen fibrous polymerizations formed by the polymerization of primary polymers by citric acid and iso-citric acid under the electronmicroscope. Only polymethymes have catalytic activity. ATPMg can disintegrate polymers into primary polymers and insester the enzyme. Long-chain lipid CoA is antagonized against the polymerization of citric acid, so they are all variant inhibitors of the enzyme.

(ii) Enzyme Molecular Chemical Modification Regulation

1. The concept of enzyme molecular chemical modification

Certain groups of enzyme molecular peptide chain can be reversible co-price modification under the catalysis of another enzyme, thus causing changes in enzyme activity, a process called enzyme-promoting chemical modification (chemical modification). Such as phosphatation and dephosphoric acid, acetylation and deacetylization, adenosineization and de-adenosineization, methylation and demethylation and -SH-S-based intermodulation, wherein phosphate and dephosphoric acid action in the metabolic regulation of substances is most common.

protein kinases are available in cells that transfer γ-phosphate groups from ATP molecules to specific protein molecular substrates, making the latter phosphorylation. Phosphate reactions can occur on serine, suline or tyrosine residues.

enzymes that are used to catalytic serine or sorine residue phosphatization are collectively referred to as protein serine/suline kinases (Protein Serine/Threonine Kinase). Enzymes that catalyse tyrosine residue phosphate are collectively referred to as protein Tyrosine Kinase.

this, there are also a variety of protein serine/sorine phosphatases in cells (ProteinSerine/Threonine Phosphotase) and protein Tyrosine Phosphotase, which remove the corresponding phosphoric acid groups.

modification of enzymes, such as modification regulation, is also an important way to rapidly regulate the metabolism of the body's substances, Table 9? lists some examples of enzyme-specific chemical modification.

table 9-2 Enzyme-specific chemical modification regulation of certain enzymes