Glycolysis reactions take place. Subsequent stages of glycolysis. Total yield of glycolysis

Anaerobic glycolysis- This is the process of oxidation of glucose to lactate, which occurs in the presence of O2.

Anaerobic glycolysis is differentiated from aerobic lichen by the manifestation of the remaining 11 reactions, the first 10 reactions are hidden in them.

Etapi:

1) The preparer, he spends 2 ATP. Glucose is phosphorylated and split into 2 phosphotrioses;

2) Stage 2 of binding with ATP synthesis. At this stage, phosphotrioses are converted into PVC. The energy of this stage is used for the synthesis of 4 ATP and the renewal of 2 NADH, which in anaerobic solutions converts PVC to lactate.

Energy balance: 2ATP = -2ATP + 4ATP

Zagalny scheme:

There is an oxidation of 1 glucose to 2 molecules of lactic acid with the creation of 2 ATP (first 2 ATP are consumed, then 4 are created). In anaerobic minds, glycolysis is a single source of energy. Summary: C6H12O6+2H3PO4+2ADP → 2C3H6O3+2ATP+2H2O.

Reactions:

Negative reactions of aerobic and anaerobic glycolysis

1) Hexokinase In meats, it phosphorylates mainly glucose, less fructose and galactose. Inhibitor of glucose-6-ph, ATP. Adrenaline activator. Insulin inducer.

Glucokinase phosphorylates glucose. Active in the liver, in the atmosphere. Glucose-6-ph does not bend. Insulin inducer.

2) Phosphohexose isomerase Aldo-ketoisomerization of closed forms of hexoses occurs.

3) Phosphofructokinase 1 Phosphorylation of fructose-6ph occurs. The reaction is non-reversible and the most effective of all reactions to glycolysis due to the liquidity of all glycolysis. Active: AMP, fructose-2,6-df, fructose-6-ph, Fn. Inhibited by: glucagon, ATP, NADH 2 citrate, fatty acids, ketone bodies. Inducer of insulin response.

4) Aldolaza A It opens the hexose form and creates a number of isoforms. For most fabrics, Aldolaza A is used. For baking and printing, Aldolaza V is used.

5) Phosphotriose isomerase.

6) 3-PHA dehydrogenase to Analyzes the creation of macroergic binding in 1,3-PHA and the renewal of NADH 2.

7) Phosphoglycerate kinase This is due to the substrate phosphorylation of ADP from the formation of ATP.

8) Phosphoglycerate mutase There is a transfer of phosphate excess from FGK from position 3 to position 2.

9) Enolase It combines a water molecule with 2-PHA and creates a high-energy binder in phosphorus. Inhibited by F - ions.

10) Pyruvate kinase This is due to the substrate phosphorylation of ADP from the formation of ATP. It is activated by fructose-1,6-df and glucose. Inhibited by ATP, NADH 2 glucagon, adrenaline, alanine, fatty acids, Acetyl-CoA. Inducer: insulin, fructose.

A single form of PVC that is stabilized and then non-enzymatically converted to the more thermodynamically stable keto form.

Anaerobic glycolysis reaction

11) Lactate dehydrogenase. Consist of 4 subunits and 5 isoforms.

Lactate is not the end product of metabolism and is eliminated from the body. From anaerobic tissue, lactate is transported by the blood to the liver, where it is converted to glucose (Measles Cycle), or in aerobic tissue (myocardium), where it is converted to PVC and oxidized to 2 and H 2 O.

Glycolysis is the process of anaerobic breakdown of glucose, which releases energy, the end product of which is pyruvic acid. Glycolysis is the final cob stage of aerobic fermentation and all types of fermentation. Glycolysis reactions occur in the small part of the cytoplasm (cytosol) and in chloroplasts.

Stages of glycolysis :

I. Preparation stage-Phosphorylation of hexose and splitting into two phosphotrioses

ІІ. First substrate is not phosphorylated(begins with 3-phospho-glyceraldehyde and ends with 3-phosphoglyceric acid. In this process, one molecule of ATP is synthesized for cutaneous phosphotriosis.)

ІІІ. Another substrate is not phosphorylated(3-phospho-glyceric acid produces phosphate and ATP as a part of intramolecular oxidation).

Activation of glucose requires expenditure of energy, which occurs during the process of creation of phosphorus esters of glucose in a number of preparatory reactions. Glucose (in its form) is phosphorylated by ATP via hexokinase, which is converted to glucose-6-phosphate, which is isomerized via glucose phosphate isomerase to fructose-6-phosphate (furanose form), which is a more labile form of molecules.

Fructose-6-phosphate is phosphorylated by phosphofructokinase from another ATP molecule. Fructose-1,6-diphosphate, which is stabilized, is a labile furanose form with symmetrically distributed phosphate groups. These groups carry a negative charge, forming one another electrostatically. This structure is easily cleaved by aldolase into two phosphotrioses - 3-phosphoglyceraldehyde (3-PGA) and phosphodioxyacetone (PDA).

3-PHA and PDA are easily converted one to one via triosephosphatisomerase. Through the splitting of the hexose molecule into two trioses, glycolyses are called inodes dichotomous path of glucose oxidation.

3-FDA begins Stage II of glycolysis - first substrate not phosphorylated. The enzyme phosphoglyceraldehyde dehydrogenase (NAD-stored SH enzyme) digests the 3-PHA enzyme-substrate complex, which involves oxidation of the substrate, transfer of electrons and protons to NAD+ and creation high-energy link(This is a bond with a very high hydrolysis energy). Next, phosphorolysis of the binder occurs: the SH enzyme is split into the substrate, and before the carboxyl group is added to the substrate, inorganic phosphate is added. The high-energy phosphate group, with the help of phosphoglycerate kinase, is transferred to ADP and created by ATP. So, in this case, a high-energy covalent phosphate bond is formed directly on the substrate, which is oxidized, such a process is called substrate phosphorylation. Ozhe, V. The results of stage II glycolysis are established by ATP and NADH renewal:

The remaining stage glycolysis - another substrate is not phosphorylated. 3-Phosphoglyceric acid, with the help of phosphoglycerate mutase, is converted into 2-phosphoglyceric acid. Next, the enzyme enolase catalyzes the splitting of water into 2-phosphoglyceric acid in the molecule, resulting in the creation of phosphoenolpyruvate, which displaces the high-energy phosphate binder Phosphoenolpyruvate phosphate stu pyruvate kinase is transmitted to ADP peruvate− terminal product of glycolysis.

Energy output to glycolysis. When one molecule of glucose is oxidized, two molecules of pyruvic acid are oxidized. When one or more substrate phosphorylation occurs, several ATP molecules are formed. However, two ATP molecules are spent on the phosphorylation of hexoses in the first stage of glycolysis. Thus, the net output of glycolytic substrate phosphorylation becomes two molecules of ATP.

In addition, at stage 2 of glycolysis, two molecules of phosphotriose are replaced by one molecule of NADH per skin. The oxidation of one NADH molecule in the electron transport cell of mitochondria in the presence of Pro 2 is associated with the synthesis of three ATP molecules, and the breakdown of two trioses (i.e., one glucose molecule) is associated with six ATP molecules. In such a manner In total, during the process of glycolysis (due to the initial oxidation of NADH), a total of ATP molecules are created. The free energy for hydrolysis of one ATP molecule in the internal cellular tissue becomes approximately 41.868 kJ/mol (10 kcal), give 335 kJ/mol or 80 kcal to all ATP molecules. This is a new energy release for glycolysis in aerobic brains.

Summary of glycolysis:

Z 6 N 12 Pro 6 + 2 ATP + 2 NAD + + 2P n + 4ADP 2 PVC + 4ATP + 2NADH

Values of glycolysis:

1) there is a connection between dichotomous substrates and the Krebs cycle;

2) supplies the client with two molecules of ATP and two molecules of NADH with the oxidation of skin glucose molecules (in the anoxia of glycolysis, perhaps, this is the main source of ATP in the client);

3) generates intermediates for synthetic processes in tissue (for example, phosphoenol peruvate, necessary for the creation of phenolic compounds and lignin);

4) in chloroplasts it provides a direct pathway for the synthesis of ATP, independent of the supply of NADPH; In addition, through glycolysis in chloroplast stores, starch is metabolized into trioses, which are then exported from the chloroplast.

U anaerobic process pyruvic acid is converted to lactic acid (lactate), which in microbiology is called lactic acid fermentation. Lactate is metabolic. in a dark corner And no matter what, it is possible to utilize lactate without oxidizing it back from peruvate.

The body is rich in protein before anaerobic oxidation of glucose. For red blood cells It is a single source of energy. Klitini skeletal muscles For the purpose of acid-free breakdown of glucose, this includes vigorous, intensive work, such as, for example, short-distance running, such as strength-training sports. Posture by physical exercises, acid-free oxidation of glucose in the cells increases during hypoxia - with various disorders anemia, at destruction of blood flow in textiles, regardless of the reason.

Glycolysis

Anaerobic transformation of glucose is localized in cytosols and includes two stages of 11 enzymatic reactions.

First stage of glycolysis

The first stage of glycolysis – preparer, here there is a loss of ATP energy, activation of glucose and its creation triose phosphates.

First reaction Glycolysis is carried out until glucose is dissolved in a reaction-generated reaction for phosphorylation of the 6th carbon atom, not included in the ring. This reaction is the first in any converted glucose, which is catalyzed by hexokinase.

Another reaction necessary for the removal of one more carbon atom from the ring for further phosphorylation (enzyme glucose phosphate isomerase). As a result, fructose-6-phosphate is stabilized.

Third reaction- enzyme phosphofructokinase phosphorylates fructose-6-phosphate from the solution of a semi-symmetrical molecule to fructose-1,6-bisphosphate. This reaction is central to the regulation of fluid glycolysis.

U fourth reaction fructose-1,6-biphosphate is cut completely fructose-1,6-diphosphate- aldolase with the synthesis of two phosphorylated triose isomers - aldose glyceraldehyde(GAF) ta ketosi dioxyacetone(DAF).

Back reaction preparatory stage - transfer to glyceraldehyde phosphate and dioxyacetone phosphate one at a time Triosephosphate isomerase. The proportion of the reaction is based on the acidity of dioxyacetone phosphate, its part being 97%, and that of glyceraldehyde phosphate – 3%. This reaction, for its simplicity, means a further fraction of glucose:

when there is a lack of energy in the cell and activation of glucose oxidation, dioxyacetone phosphate is converted into glyceraldehyde phosphate, which is further oxidized at another stage of glycolysis,
With a sufficient amount of ATP, however, glyceraldehyde phosphate is isomerized into dioxyacetone phosphate and the rest is sent for fat synthesis.

Another stage of glycolysis

Another stage of glycolysis is released energy that is contained in glyceraldehyde phosphate, which is stored in the form ATP.

Shosta reaction glycolysis (enzyme glyceraldehyde phosphate dehydrogenase) – oxidation of glyceraldehyde phosphate and addition to new phosphoric acid leads to the formation of the macroergic form of 1,3-diphosphoglyceric acid and NADH.

U seventy reactions(enzyme phosphoglycerate kinase) the energy of the phosphoester linkage, stored in 1,3-diphosphoglycerate, is spent on the creation of ATP. The reaction has an additional name - which specifies the source of energy for the release of macroergic binding in ATP (as a substrate of the reaction) in the form of oxide phosphorylation (as an electrochemical gradient and water on the mitochondrial membrane).

Eighth reaction– syntheses in the forward reaction of 3-phosphoglycerate under infusion phosphoglycerate mutase Isomerizes to 2-phosphoglycerate.

Ninth reaction- enzyme enolase energizes a water molecule from 2-phosphoglyceric acid and creates a macroergic phosphoester binder in the phosphoenolpyruvate warehouse.

Tenth reaction glycolysis – another one substrate phosphorylation reaction– lies in the transfer of macroergic phosphate by peruvate kinase from phosphoenolpyruvate to ADP and dissolved peruvic acid.

Glycolysis is the process of anaerobic breakdown of glucose, which releases energy, the end product of which is pyruvic acid (PVA). Glycolysis is the final cob stage of aerobic fermentation and all types of fermentation. Glycolysis reactions occur in a small part of the cytoplasm (cytosol) and chloroplasts. In the cytosol, glycolytic enzymes are inversely associated with multienzyme complexes with the participation of filaments. This organization of multi-enzyme complexes ensures vectoriality of the processes.

In general, the whole process of glycolysis is not deciphering. Biochemists G. Embden and O. Meyerhof, as well as the Polish biochemist J. O. Parnas.

Glycolysis is divided into three stages:

1. Preparatory stage – phosphorylation of the hexose and its splitting into two phosphotrioses.

2. First substrate phosphorylation, which begins with 3-PHA and ends with 3-PHA. The oxidation of an aldehyde to an acid is associated with increased energy. In this process, cutaneous phosphotriosis synthesizes one ATP molecule.

3-FDA → 3-FGK

3. Secondary substrate phosphorylation, in which 3-PHA provides phosphate with ATP as a component of intramolecular oxidation.

3-PDA → 2-FGK → PEP → PVK

Glucose fragments are stable, their activation requires the expenditure of energy, which occurs in the process of the creation of phosphorus esters of glucose in a number of preparatory reactions. Glucose (in its early form) is phosphorylated by ATP through hexokinase, which is converted to glucose-6-phosphate through glucose phosphate isomerase. This process is necessary for the creation of the labile furanose form of the hexose molecule. Fructose-6-phosphate is phosphorylated by phosphofructokinase from another ATP molecule.

Fructose-1,6-diphosphate is a labile furanose form with symmetrically distributed phosphate groups. These groups carry a negative charge, forming one another electrostatically. This structure is easily cleaved by aldolase into two phosphotrioses – 3-PHA and PDA, which are easily converted one to one by triosephosphate isomerase.

With 3-PHA, another stage of glycolysis begins. The enzyme phosphoglyceraldehyde dehydrogenase creates an enzyme-substrate complex with 3-PHA, which involves the oxidation of the substrate and the transfer of electrons and protons to NAD+. During the oxidation of PHA to PGA in the enzyme-substrate complex, the mercaptanium of a high-energy linkage is blamed. Next, phosphorolysis of this binding occurs, as a result, the SH enzyme is separated from the substrate, and before the carboxyl group is added to the substrate, inorganic phosphate is added. The high-energy phosphate group, with the help of phosphoglycerate kinase, is transferred to ADP and ATP is created. Thus, as a result of another stage of glycolysis, ATP and NADH are created.

Small Stages of glycolysis. The dotted line indicates workarounds for animal glycolysis.

The remaining stage of glycolysis is another substrate phosphorylation. 3-PHA, with the help of phosphoglycerate mutase, is converted to 2-PHA. Next, the enolase enzyme catalyzes the splitting of a water molecule into 2-PHA. This reaction is accompanied by a redistribution of energy in the molecule, as a result of which PEP is created - connected to a high-energy phosphate binder. This phosphate, through the participation of pyruvate kinase, is transferred to ADP and is converted by ATP, and enolpruvate is converted into a more stable form - pyruvate - the end product of glycolysis.

Energy output to glycolysis. Two molecules of ATP are consumed to stabilize fructose-1,6-biphosphate. During the course of two substrate phosphorylations, 4 ATP molecules are synthesized (divided into two trioses). The total energetic result of glycolysis is 2 molecules of PTP. In the process of glycolysis, 2 molecules of NADH are also synthesized, the oxidation of which in aerobic brains leads to the synthesis of 6 more molecules of ATP. Therefore, in aerobic brains the total energy output becomes 8 ATP molecules, in anaerobic brains – 2 ATP molecules.

Functions of glycolysis in cells.

1. there is a connection between dichotomous substrates and the Krebs cycle;

2. energy value;

3. synthesizes intermediates necessary for synthetic processes in cells (for example, PEP is necessary for the synthesis of lignin and other polyphenols);

4. In chloroplasts, glycolysis provides a direct pathway for the synthesis of ATP; through glycolysis, starch is broken down into triose.

Regulation of glycolysis You can work in three stages:

1. Glucose-6-phosphate allosterically inhibits the activity of the hexokinase enzyme.

2. The activity of phosphofructokinase increases when ADP is added instead and is suppressed by high concentrations of ATP.

3. Peruvate kinase is inhibited by high concentrations of ATP and acetyl-CoA.

2. Interrelationship between movement and fermentation

FERMENTATION- enzymatic breakdown of organic compounds, especially carbohydrates, which is accompanied by the creation of ATP. May be present in the organisms of animals, plants and many others. microorganisms without or without participation Pro 2 (respectively, anaerobic or aerobic fermentation).

In 1875 The German physiologist E. Pflueger showed that a toad, placed in a medium without sourness, loses its life every hour and at which it sees 2. Vin called this type of death intramolecular. This idea was supported by the German physiologist Roslin W. Pfeffer. Based on these experiments, two theories were developed to describe the chemistry of food:

C 6 H 12 Pro 6 →2 C 2 H 5 VIN +2 CO 2

2 C 2 H 5 ВІН + 6О 2 → 4СО 2 + 6Н 2 О

It was reported that in anaerobic tanks, glucose is broken down into ethyl alcohol and CO 2. At another stage, the alcohol is oxidized with acid from carbon dioxide and water.

Analyzing the concepts developed by Pfeffer and Pflueger, S.P. Kostychev (b. 1910) developed a concept that is consistent in its effectiveness, because ethanol can be an intermediate product of normal aerobic digestion in plants for two reasons: 1 – alcoholic wine, 2 – it is oxidized by plant tissues, which are much thicker and lower in glucose. Having let the bones pass, the process of fermentation and fermentation is knitted through some intermediate product. Then, according to the robots of Kostichev and the German biochemist K. Neuberg, this substance was discovered, and they discovered pyruvic acid (PVA):

PVC → 2CH 3 CHONCOOH (fermented lactic acid)

PVC → 2СО 2 + 2С 2 Н 5 ВІН (alcohol fermentation)

Z 6 H 12 Pro 6 → 2CH 3 COCOOH → 2CO 2 + 2CH 3 COOH (fermentation oxide)

PVC → 6СО2 + 6Н2О (dikhannya)

Lactic acid and alcohol fermentation go in anaerobic waters, fermentation and alcohol fermentation go into aerobic waters.