1. 미생물의 대사-1
Microbial Metabolism

2. 미생물 세포의 성분(대장균)
_______________________________________________________________
% total weight % dry weight
____________________________________________________________________________________________________________________________________________ 물
유기물
단백질(proteins)
핵산(nucleic acids)
RNA
DNA
탄수화물(carbohydrates)
지방(lipids)
기타 유기물
무기물 _____________________________________________________________________________________________________________________________________________

3. 미생물 세포의 성분(대장균) 원소 % dry weight 탄소 (C, carbon) 50 산소 (O, oxygen) 20
_______________________________________________________________________________________________________________
원소 % dry weight
___________________________________________________________________________________________________________
탄소 (C, carbon) 50
산소 (O, oxygen) 20
질소 (N, nitrogen) 14
수소 (H, hydrogen)
인 (P, phosphorous) 3
황 (S, sulfur)
칼륨 (K, potassium)
나트륨 (Na, sodium)
칼슘 (Ca, calcium)
마그네슘(Mg, magnesium)
염소 (Cl, chloride)
철 (Fe, iron)
기타 (Mn, Zn, Mo, Cu, Co, …) _____________________________________________________________________________________________________________

4. Carbon
Oxygen
Hydrogen
Nitrogen
Phosphate
Sulfur
Magnesium
Manganese
Potassium
Calcium
Sodium
Iron
Zinc …

5. Sugars, Polysaccharides (Carbohydrates)

6. Amino acids, Proteins

7. Fatty acids, Lipids

8. Nucleic acids

9. Vitamins

10. 영양요구성에 따른 미생물의 분류 에너지원 요구성 탄소원 요구성 에너지원 및 탄소원 요구성에 따른 생물의 분류 에너지원 탄소원
광영양 (phototroph)
화학영양 (chemotroph)
전자를 얻는 방법에 따라 : 무기화합물 (chemolithotroph)
유기화합물 (chemoorganotroph)
탄소원 요구성
독립영양(autotroph) : 무기탄소화합물 (CO2)
종속영양(heterotroph) : 유기탄소화합물 (탄수화물, 지질, 단백질)
에너지원 및 탄소원 요구성에 따른 생물의 분류
에너지원 탄소원
광합성 독립영양 빛 이산화탄소
광합성 종속영양 빛 유기화합물
화학합성 독립영양 무기화합물 이산화탄소
화학합성 종속영양 유기화합물 유기화합물

11. 에너지원과 탄소원에 따른 미생물의 분류 병원 미생물은? . 광합성 독립영양 (photoautotroph)
조류, 광합성세균, (식물)
. 광합성 종속영양 (photoheterotroph)
홍색세균, 녹색세균
. 화학합성 독립영양 (chemoautotroph, chemolithotroph)
철세균, 황세균, 수소세균, 질화세균
. 화학합성 종속영양 (chemoheterotroph)
대부분의 미생물, (동물)
병원 미생물은?

12. 대사작용(Metabolism) 대사작용 (물질대사) 이화대사 (분해대사, Catabolism)
- 세포 안에서 일어나는 모든 생화학 반응
- 모든 대사작용은 생체촉매인 효소의 작용으로
- 대사작용은 이화대사(분해대사)와 동화대사(합성대사)로 구별
이화대사 (분해대사, Catabolism)
- 영양소를 분해하고 산화시켜
세포 구성물질의 합성에 사용할
에너지, 환원력, 저분자 물질(전구체, precursor)을 만드는 과정
동화대사 (합성대사, Anabolism)
- 에너지, 환원력, 저분자 물질(전구체)을 이용하여
세포 구성 성분을 합성하는 과정
☞ 이화작용과 동화작용은 수많은 대사경로로 이루어짐
각 대사경로는 다수의 효소반응으로 이루어짐
각 대사경로는 긴밀한 상호작용을 함

13. 화학 에너지 획득 Chemical energy 화학 에너지 획득 방법 high energy phosphate : ATP, …
reducing agent : NADH, NADPH, FADH2
화학 에너지 획득 방법
. 호기적 호흡 (Aerobic respiration)
최종 전자수용체로 O2 사용
. 혐기적 호흡 (Anaerobic respiration)
최종 전자수용체로 산소 대신 무기산화물 (NO3-, SO42-, CO2)
또는 유기물 사용
* 발효 (fermentation)
- 혐기적 상태에서 일어나는 에너지 생성 대사
- 포도당, 유기화합물을 전자전달체로 사용 (부분적인 산화)
전자전달계를 이용하지 않음
- ethanol, acetic acid, lactic acid 등 생산

14. 고에너지 인산 화합물 세포 내에서 에너지는 주로 ATP 형태로 생성/저장/전달
ATP (adenosine triphosphate)
. 고에너지 인산기(~P)를 가짐 : 고에너지 인산 화합물
. ATP가 가수분해 될 때에는 에너지가 방출됨
ADP 또는 AMP로부터 ATP로 될 때에는 에너지가 소모됨
ATP + H2O ⇌ ADP + Pi + H+, ΔGo = -7.3 kcal/mol
ADP + H2O ⇌ AMP + Pi + H+, ΔGo = -7.3 kcal/mol
. GTP, UTP, CTP 등도 고에너지 인산기를 저장 또는 전달함
NADH, NADPH, FADH2
. 전자전달계/산화적 인산화를 거쳐 ATP로 전환

15. 환원력(reducing power) 대사과정에서 만들어진 수소 원자들(환원력)은 주로
전자전달분자(NAD+, NADP+, FAD)에 의해 저장∙운반됨
. NAD+ (NADH) : nicotinamide adenine dinucleotide
. NADP+ (NADPH) : nicotinamide adenine dinucleotide phosphate
. FAD (FADH2 ) : flavine adenine dinucleotide
NADH, NADPH, FADH2
. 전자전달계/산화적 인산화를 거쳐 ATP로 전환

16. 에너지 생성 대사 세포는 생합성, 영양소의 수송, 기초대사, 운동 등을 수행하기 위해 에너지를 필요로 함
대부분의 세포는 탄소화합물(주로 탄수화물)을 분해하는
이화작용(분해대사)을 통해 에너지를 얻음
- 광합성 생물(식물, 광합성 미생물)은 H2O와 CO2로부터
탄수화물을 합성하여 에너지 생산에 이용
- 광합성을 하지 않는 생물체는 탄수화물을 섭취하여 이용
에너지 생성에 사용되는 주요 고분자 물질 : 탄수화물, 지방, 단백질
1. 고분자 물질은 세포 밖에서 가수분해효소에 의해 분해되어,
단당류, 지방산, 글리세롤 등의 작은 분자가 되어 세포 안으로 흡수됨
2. 단당류, 지방산, 글리세롤 등은 acetyl Co-A 및 기타 물질로 변환되어
3. TCA cycle에 이입되어 ATP, NADH, NADPH, FADH2 생산
4. NADH, NADPH, FADH2 는 전자전달계를 거쳐 산화적 인산화에 의해
ATP로 변환됨

17. Catabolism

18. 중요한 에너지 생성 대사(포도당) 해당과정(Glycolysis) EMP NADH
Glucose → HMP → Pyruvate → TCA → NADPH → 전자전달계 → ATP
EDP FADH 산화적 인산화
해당과정(Glycolysis)
. EMP pathway (Embden-Meyerhof-Parnas pathway)
Occurs, with variations, in nearly all organisms
Aerobic or Anaerobic
. Glucose + 2 NAD+ + 2 ADP + 2 Pi →
2 Pyruvate + 2 (NADH + H+) + 2 ATP + 2 H2O
. Pyruvic acid ⇒ ethanol, lactic acid, … (혐기적 조건에서, 발효)
* Substrate-level phosphorylation (기질수준의 인산화)
ATP generated directly at the point of reaction
* 넓은 의미의 Glycolysis는 EMP, HMP, EDP를 포함함

19. Glycolysis

20. 5탄당 인산 경로 (Pentose phosphate pathway, PPP)
. Hexose monophosphate (HMP) shunt
Phosphogluconate pathway
. Primary role is anabolic rather than catabolic
Reducing equivalent (NADPH)
reductive biosynthesis reactions (e.g. fatty acid synthesis)
Pentoses (ribose-5-phosphate)
synthesis of nucleotides and nucleic acids.
Erythrose-5-phosphate
synthesis of aromatic amino acids
Ribulose-1,5-biphosphate (from ribulose-5-phosphate)
CO2 fixation
. Oxidative phase : generation of NADPH
Non-oxidative phase : synthesis of 5-carbon sugars

21. Pentose phosphate pathway

22. Entner-Doudoroff pathway
. Occurs only in some prokaryotes Gram (-) : Pseudomonas, Rhizobium, Azotobacter,
Agrobacterium, Escherichia coli,
Zymomonas mobilis, Xanthomonas campestris
Gram (+) : Enterococcus faecalis
. Glucose → Pyruvate
Uses 6-phosphogluconate dehydratase &
2-keto-3-deoxyphosphogluconate aldolase
1 Glucose → 1 ATP + 1 NADH + 1 NADPH
(EMP, PPP : 1 Glucose → 2 ATP + 2 NADH)

23. Entner-Doudoroff pathway (Zymomonas mobilis)

24. TCA cycle(Tricarboxylic acid cycle)
. Krebs cycle, Citric acid cycle (구연산 회로)
. Used by all aerobic organisms
from Pyruvate (from carbohydrates, fats and proteins)
under aerobic condition
to generate chemical energy
1 Pyruvate → 3 CO2 + 4 (NADH + H+) + 1 FADH2 + 1 GTP
→ ATP
. Intermediates : precursors of certain amino acids, etc.
NADH : reducing agent used in numerous biochemical reactions

25. TCA cycle

26. 전자전달 (Electron transport)
. Glycolysis/TCA cycle에서 생성된 (NADH + H+)와 FADH2 가
전자전달계를 거쳐 산화되면서 ATP가 만들어짐
. Redox reaction
Electron donor (전자 공여체) : (NADH + H+), FADH2
Electron acceptor (전자 수용체) : O2
. Electron transport chain (ETC) :
Electron carriers (전자 운반체) : cytochromes
Eukaryotes : inner mitochondrial membrane
thylakoid membrane of chloroplast
Bacteria : in cell membrane
The energy released by electrons flowing through ETC is
used to transport protons across the membrane.
(generation of proton gradient)

27. Oxidative phosphorylation (OXPHOS, 산화적 인산화)
Chemiosmosis (화학적 삼투)
. The transport of electrons thru ETC
. The transport of protons across the membrane generates
potential energy in the form of electrochemical proton
gradient across the membrane.
. The potential energy is used (tapped) by ATP synthase
to generate ATP
. ATP synthase use the potential energy to generate ATP
from ADP by phosphorylation.
. 1 (NADH + H+) ⇒ 3 ATP 1 FADH2 ⇒ 2 ATP
Oxidative phosphorylation (OXPHOS, 산화적 인산화)
Substrate-level phosphorylation (기질수준의 인산화)
Production of reactive oxygen species
Superoxide, hydrogen peroxide, free radicals

28. Inhibitors of electron transport (전자전달 저해제)
. Competitive inhibitors of Electron Transport Chain (ETC)
Bind to some of the components of the ETC
Inhibit electron transport
Amytal, Rotenone, Antimycin A, CO, Azides, Cyanides,
Piericidin, Carbon monoxide, Hydrogen sulfide
. Uncouplers of oxidative phosphorylation
Inhibit the coupling between the electron transport and
phosphorylation reactions
Disrupt the proton gradient → inhibit ATP synthesis
Ditrophenol, Valinomycin
. Poison? Drug?

29. Fermentation Fermentation (발효)
. Production of alcoholic beverages or other fermented foods
. Large-scale microbial process (with or without air)
. Energy-releasing anaerobic metabolic process
. Energy (ATP) production (in the lack of oxygen)
from sugar or other organic molecules (electron donor)
using an organic molecule as the final electron acceptor
Conversion of sugar to acids, gases or alcohol
Yeast, bacteria, oxygen-starved muscle cells
. Lactic acid fermentation (Homolactic, Heterolactic)
. Formic acid fermentation
. Ethanol fermentation …

30. Anaerobic respiration
Anaerobic respiration : respiration without oxygen
. Respiration using electron acceptors other than oxygen
. Uses a respiratory electron transport chain
Generate ATP by oxidative phosphorylation
. Terminal electron acceptors :
Less-oxidizing (smaller reduction potential) than O2
sulfate (SO42−), sulphur (S0), nitrate (NO3−), ferric iron (Fe3+)
fumarate, carbon dioxide (CO2), HASO42-, SeO42-
Less energy is released per oxidized molecule
. Energetically less efficient than aerobic respiration
more efficient than fermentation
. Mainly by prokaryotes (facultative or obligate anaerobes)

31. β-oxidation of fatty acids

32. Photosynthesis

33. Photosynthesis Photosynthesis
. Greek phōs, ‘light’ ; synthesis, ‘putting together’
. Conversion of light energy into chemical energy
The chemical energy is stored in carbohydrate molecules,
which are synthesized from carbon dioxide and water
. CO2 + electron donor + light energy →
carbohydrate + oxidized electron donor + H2O
. In oxygenic photosynthesis
n CO2 + 2n H2O + photons → (CH2O)n + n O2 + n H2O
n CO2 + n H2O + photons → (CH2O)n + n O2
H2O : reactant (electron donor in light-dependent reaction
product (electron accoptor in light-independent rx.

34. Photosynthesis Photosynthesis Calvin cycle, Reverse Krebs cycle
1. Light dependent reactions
Conversion of light energy into chemical energy
Capture the energy of light &
Use it to make the energy-storage molecules ATP & NADPH
2. Light-independent reactions
Storage of the chemical energy (carbohydrate)
Use ATP and NADPH to capture and reduce carbon dioxide
CO2 is converted into sugars (carbon fixation)
Calvin cycle, Reverse Krebs cycle
. Photoautotroph
Photoheterotroph
. Oxygenic photosynthesis
Anoxygenic photosynthesis

35. Light-dependent reaction (명반응)
. On the thylakoid membranes (chloroplast/plasma membrane)
Four major protein complexes
Photosystem II (PSII)
Cytochrome b6f complex
Photosystem I (PSI)
ATP synthase
. Begin with the absorption of photon by chlorophyll a
within a reaction center of Photosystem II
Photosystems II & I
protein complexes that absorb photons
use the energy to create an electron transport chain
. ATP and NADPH produced
. Net-reaction (oxygenic photosynthesis)
2H2O + 2NADP+ + 3ADP + 3Pi → O2 + 2NADPH + 3ATP

37. Light-independent Reactions
. Conversion of CO2 into glucose
In the stoma of chloroplast
the fluid-filled area outside of the thylakoid membranes
Occurs only when light is available (dark reaction ?)
. Calvin cycle : plants, algae, cyanobacteria
Reverse Krebs cycle :
. Calvin cycle : fixation of CO2
Use the ATP and NADPH produced by light-dependent rxs.
CO2 is incorporated into already existing organic carbon
compounds, such as ribulose bisphosphate (RuBP)
3 CO2 + 6 NADPH + 5 H2O + 9 ATP
→ G3P + 2 H+ + 6 NADP+ + 9 ADP + 8 Pi
G3P = glyceraldehyde-3-phosphate
Pi = inorganic phosphate

38. Calvin cycle 1. Carboxylation of RuBP by RuBisCO
Incorporation of CO2 into RuBP : generation of 2x 3-PGA
RuBP : ribulose 1,5-bisphosphate (C5)
RuBisCO : RuBP carboxylase/oxygenase
3-PGA : 3-phosphoglycerate (3-phosphoglyceric acid ) (C3)
2. Reduction of 3-PGA to G3P
Using the ATP & NADPH
phosphoglycerate kinase
glyceraldehyde 3-phosphate (G3P) dehydrogenase
3. Regenerqtion of RuBP
Generation of 3 RuBP molecules from 5 G3P molecules
using 3 molecules of ATP
* Net : Production of 1 G3P from 3 CO2
at the expense of 9 ATP & 6 NADPH

40. Calvin cycle 3 CO2 + 6 NADPH + 5 H2O + 9 ATP
→ G3P + 2 H+ + 6 NADP+ + 9 ADP + 8 Pi
2 G3P → 1 Glucose

41. Gluconeogenesis Gluconeogenesis (GNG, 포도당 신생경로)
. Generation of glucose from non-carbohydrates
Pyruvate, lactate, glycerol, citric acid cycle intermediates,
and glucogenic amino acids, (and some fatty acids)
. Glycolysis vs Gluconeognesis : 4 irreversible reactions
pyruvate carboxylase : pyruvate → oxaloacetate
PEP carboxykinase : oxaloacetate → phosphoenolpyruvate
fructose-1,6-bisphosphatase : F-1,6-diP → F-6-P
glucose 6-phosphatase : G-6-P → glucose
. To maintain blood glucose level (to avoid hypoglycemia)
Gluconeogenesis
a target of therapy for type 2 diabetes
antidiabetic drug : metformin
. Glycogenolysis : glycogen to glucose