해당과정

해당과정(Glycolysis)

- Glycolysis Is an Energy-Conversion Pathway in Many Organisms

- The Glycolytic Pathway Is Tightly Controlled - Gluconeogenesis(포도당신생과정) and

Glycolysis(해당과정) Are Reciprocally Regulated

Glycolysis: a cytosolic and plastidic process

• from glykos, an older term for glucose + -lysis degradation

• is a metabolic pathway that converts glucose (C₆H₁₂O₆) into pyruvate (C₃H₅O₃^-).

• Glycolysis converts carbohydrates into pyruvate, producing NADH and ATP.

• a key metabolic feature of the respiratory process of the plant cell and is particularly important in the cells of germinating seedlings and in

nonphotosynthetic cells of the mature plant.

• occurs in nearly all organisms, both aerobic and anaerobic.

Figur 16.1 Some fates of glucose.

해당은 한 분자의 글루코오스를 두 분자의 피루브산으로 대사하며 연속으로 일어자는 반응.

First stage of glycolysis.

Hexokinase traps glucose in the cell and begins glycolysis(해당과정의 시작은 글루코스로부터 6-인산 글루코스로 전환과정 임)

디히드록시 아세톤인산

글리세랄 알데히드 3- 인산

Reactions of plant glycolysis and fermentation

In the main pathway, sucrose is oxidized via hexose phosphates and triose phosphates to the organic acid pyruvate, but plants also carry out alternative reactions.

The double arrows denote reversible reactions; the single arrows, essentially irreversible reactions.

Initial phase of glycolysis

• Substrates from different sources are channeled into triose phosphate.

• For each molecule of sucrose that is metabolized, four molecules of triose phosphate are formed. The process requires an input of up to 4 ATP.

Energy-conserving phase of glycolysis

• Triose-phosphate is converted to pyruvate.

• NAD⁺ is reduced to NADH by glycerabldehyde-3-phosphate dehydrogenase.

• ATP is synthesized in the reactions catalyzed by phosphoglycerate kinase and pyruvate kinase.

• An alternative end product, phosphoenolpyruvate (PEP), can be converted to malate for mitochondrial oxidation or storage in the vacuole.

• NADH can be reoxidized during fermentation by either lactate dehydrogenase or alcohol dehydrogenase.

Glucose + 2 NAD⁺ + 2 P_i + 2 ADP → 2 pyruvate + 2 NADH + 2 ATP + 2 H⁺ + 2 H₂O

Reactions of plant glycolysis and fermentation: structures of the intermediates

해당과정의 첫번째과정은 글루코스로부터 프럭토오스 6 인산을 생산하는것임

해당과정의 첫번째과정은 글루코스로부터 프럭토오스 6 인산을 생산하는것임

첫번째 과정의 마지막은 1,6 프록토오즈로 부터 DHAP 와 GAP 3탄당을 생산하여 프루브산을

생성하기 위한 두번째 단계로 들어간다

Second stage of glycolysis.

The oxidation of an aldehyde to an acid powers the formation of a compound with high phosphoryl-

transfer potential

글리세랄알데하이드 3 인산 알데하드기에 다시 인이 붙어 1,3 비스포스포글리세르산이 형성된후 3 인산

글리세레르산으로 전환됨

1. Glyceraldehyde 3-phosphate, an aldehyde, is oxidized to 3-phosphoglycerate, a carboxylic acid.

2. NAD⁺ is concomitantly reduced to NADH.

3. ATP is formed from P_i and ADP at the expense of carbon-oxidation energy.

3 인산 글리세르산은 두개의 ATP를 생성하면서 최종적으로 피루브산을 생성한다

Pyruvate ??? 어디로

Figure 16.10 Active site of alcohol dehydrogenase.

1. Ethanol is formed from pyruvate in yeast and several other microorganisms. (산소가 없는 조건)

2. Lactate is formed from pyruvate in a variety of

microorganisms in a process called lactic acid fermentation.

3. Only a fraction of the energy of glucose is released in its anaerobic conversion into ethanol or lactate. 산소가 있는

조건에서는 시트르산회로를 통한 더 많은 에너지를 생산하게 됨

Pyruvate + NAD⁺ + CoA y acetyl CoA + CO₂+ NADH + H

pyruvate dehydrogenase

pyruvate + CoA + NAD⁺  acetyl-CoA + CO₂ + NADH + H⁺

Figure 16.18 Regulation of glycolysis in muscle.

The regulation of glycolysis in the liver illustrates the biochemical versatility

of the liver

Glycolysis in Plant

락트산의 피브르산으로 전환 및 glcose 로 전환.