Name: pyruvate pathways in fermentation
Uploaded: 2025-05-22T09:05:36.000Z
Duration: 1 min 20 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.18

SC.912.L.18.8

Fates of Pyruvate

해당작용(glycolysis)의 최종 산물인 피루브산(Pyruvate)은 유기체 내부의 생리학적 조건에 따라 여러 대사 운명을 가질 수 있습니다.
호기성 조건에서 피루브산은 아세틸 코엔자임 A로 전환된 다음 TCA 회로와 전자 전달 사슬을 통해 전달되어 ATP 형태의 에너지를 생성합니다.
그러나 혐기성 조건에서는 효모와 혐기성 박테리아에서 볼 수 있듯이 전자 전달 사슬이 작동하지 않습니다. 따라서 피루베이트는 에탄올로 발효되고 NADH는 NAD+로 산화됩니다. 그런 다음 NAD+는 해당과정으로 다시 재활용됩니다.
대부분의 척추동물에서 일시적인 저산소 상태는 또 다른 형태의 피루브산 발효를 유발하여 젖산으로 발효되어 NAD+를 생성합니다.
발효 중 NAD+의 재생은 해당과정을 통해 세포가 저산소 상태에서도 ATP를 계속 생성하는 데 도움이 됩니다.
혈당 수치가 낮을 때 피루브산은 포도당 신생(gluconeogenesis)이라는 과정을 통해 포도당 6-인산염으로 다시 전환될 수도 있습니다. 그런 다음 포도당 6-인산염은 포도당으로 전환되어 혈당 수치를 회복합니다.

피루브산의 운명

피루브산은 포도당이 피루브산으로 산화되는 동시에 NAD+를 NADH로 환원시키는 해당과정의 최종 산물입니다. 두 분자의 ATP도 기질 수준 인산화에 의해 생성됩니다.

호기성 유기체에서 피루브산은 시트르산 회로를 통해 대사되어 환원된 조효소 NADH 및 FADH2를 생성합니다. 이러한 조효소는 전자 전달 사슬에서 산화되어 ATP를 생성하고 그 과정에서 NAD+와 FAD를 재생성합니다. 일부 세포 유형 및 유기체에서 볼 수 있듯이, 발효는 산소가 없을 때 피루브산을 젖산으로 감소시켜 NADH를 NAD+로 산화시킵니다. NAD+의 재생은 해당과정이 기질 수준 인산화에 의해 계속해서 ATP를 만들 수 있게 합니다.

젖산발효

젖산 발효 동안 피루브산은 NADH로부터 전자를 받아 젖산으로 환원됩니다. 동종유산 발효를 수행하는 미생물은 발효산물로서 젖산만을 생산합니다. 이종유산 발효를 수행하는 미생물은 젖산, 에탄올 및/또는 아세트산과 CO2의 혼합물을 생성합니다. 정상적인 미생물군에 의한 젖산 생산은 특정 신체 부위에서 병원균의 성장을 방지하고 위장관 건강에 중요합니다.

에탄올 발효

맥주효모균에 의한 피루브산의 에탄올 발효는 알코올 음료 생산에 사용되며 CO2 생성으로 인해 빵 제품의 품질도 향상됩니다. 식품 산업 외부에서 식물 제품의 에탄올 발효는 바이오 연료 생산에 중요합니다.

몇몇 발효 제품은 식품 산업 외부에서 상업적으로 중요합니다. 예를 들어, 아세톤-부탄올-에탄올 발효 과정에서 아세톤, 부탄올과 같은 화학 용매가 생성됩니다. 항생제(예: 페니실린), 백신, 비타민에 사용되는 복합 유기 제약 화합물은 혼합산 발효를 통해 생산됩니다.

이 텍스트는 다음에서 수정되었습니다 <a href="https://openstax.org/books/biology-2e/pages/7-5-metabolism-without-oxygen">Openstax, Biology 2e, Section 7.5: Metabolism without oxygen</a>

피루브산은 해당과정의 최종 산물로, 포도당이 피루브산으로 산화되는 동시에 NAD+를 NADH로 환원시킵니다. ATP의 두 분자는 또한 ...

Education

교육

JoVE Core

Cell Biology

세포생물학

Unit 1

제1단원

Introduction to Metabolism

신진대사 입문

KEY TERMS AND CONCEPTS

주요 용어 및 개념

pyruvate pathways in fermentation

Pyruvate is a key product of glycolysis and can follow different pathways depending on oxygen availability. During glycolysis, glucose is oxidized to pyruvate, NAD+ is reduced to NADH, and two ATP are made by substrate-level phosphorylation. In aerobic organisms, pyruvate then enters the citric acid cycle, which helps produce the reduced coenzymes NADH and FADH2. These coenzymes are later oxidized in the electron transport chain to make ATP and regenerate NAD+ and FAD.

When oxygen is absent, some cells and organisms use fermentation to keep energy production going. Fermentation reduces pyruvate to lactate and oxidizes NADH back to NAD+. This regeneration of NAD+ is important because it allows glycolysis to continue making ATP by substrate-level phosphorylation.

In lactic acid fermentation, pyruvate accepts electrons from NADH and becomes lactic acid. Microbes that carry out homolactic fermentation make only lactic acid. Microbes that carry out heterolactic fermentation make a mix of lactic acid, ethanol and/or acetic acid, and CO2. Lactic acid made by normal microbiota can help prevent pathogen growth in some body regions and supports gastrointestinal tract health.

Pyruvate can also be fermented to ethanol by the yeast Saccharomyces cerevisiae. This process is used to make alcoholic beverages and helps bread rise because it releases CO2. Ethanol fermentation of plant products is also important in biofuel production. Other fermentation products have commercial value too. Acetone and butanol are made during acetone-butanol-ethanol fermentation, and complex organic compounds used in antibiotics such as penicillin, vaccines, and vitamins are produced through mixed acid fermentation.

Pyruvate Pathways in Fermentation

overview of metabolism

Metabolism in Plants, Animals, and Microbes

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fates of pyruvate

Pyruvate is a key product of glycolysis and can follow different pathways depending on oxygen availability. During glycolysis, glucose is oxidized to pyruvate, NAD+ is reduced to NADH, and two ATP are made by substrate-level phosphorylation. In aerobic organisms, pyruvate then enters the citric acid cycle, which helps produce the reduced coenzymes NADH and FADH2. These coenzymes are later oxidized in the electron transport chain to make ATP and regenerate NAD+ and FAD. When oxygen is absent,...

role of reduced coenzymes nadh and fadh&#8322;

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sugars as energy storage molecules

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key terms and concepts

Explore how pyruvate is used in aerobic respiration and fermentation, including lactic acid and ethanol fermentation, ATP production, and real-world uses.

Pyruvate Pathways in Fermentation | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

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SC.912.L.18.7

A. All living things are composed of four basic categories of macromolecules and share the same basic needs for life.

B. Living organisms acquire the energy they need for life processes through various metabolic pathways (primarily photosynthesis and cellular respiration).

C. Chemical reactions in living things follow basic rules of chemistry and are usually regulated by enzymes.

D. The unique chemical properties of carbon and water make life on Earth possible.

Pyruvate Pathways in Fermentation

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