Embed Size (px)
Citation preview
1
MicrobiologyMicrobial Metabolism IIntroduction to MetabolismChing-Tsan Huang (黃慶璨)Office: Room 111, Agronomy HallTel: (02) 33664454E-mail: [email protected]
2
IntroductionWhy study microbiology?To control and utilization of MICR RGANI$M$
Physiology: The study of life processes in living cellsMetabolism: The total of all chemical reactions in cells
Why microbial metabolism?
TransportChemical Work
Mechanical
Heat
CatabolismAnabolism
PhotosynthesisMaintenance
GrowthRespiration
ReproductionFermentation
MetabolismPhysiologyLight Energy
3
Substrates Products
EnergyCatabolismAnabolism
Light Energy
Photosynthesis
Enzymes
Overview of metabolism
Purpose: Trapping, generation and use of energyWhere: within cells (under controlled temperature and pH) How: catalyzed by enzymes
4
Metabolism of microorganismsInterchangeable
Macro- to micro-molecules or vice versa
PolysaccharidesLipidsProteinsNucleic acids
MonosaccharidesFatty acids, glycerolAmino acidsNucleotides
CO2H2O, O2NH4
+, NO3-
PO4-, SO4
=
CatabolismAnabolism
Polymers Monomers Molecules
5
Oxidation-Reduction ReactionElectron CarriersATP (adenosine triphosphate)
Reaction and Energy
Without enzyme
With enzyme
6
Oxidation-Reduction Reaction
7
Electron Transport Systems
NADH
8
Electron CarriersTransfer electrons between different locationsEnergy flow in metabolism
NAD+ nicotinamide adenine dinucleotideNADP+ nicotinamide adenine dinucleotide phosphate
9
ATP: Adenosine TriPhosphateA high-energy moleculeATP + H2O ADP + Pi ΔGo’ = -7.3 kcal/mol
10
Apoenzymeprotein component of an enzyme
Cofactornonprotein component of an enzyme
prosthetic group – firmly attachedcoenzyme – loosely attached
Holoenzyme = apoenzyme + cofactorCoenzyme
often act as carriers, transporting substances around the cell
Enzyme Structure
11
Enzymes: Classification
OxidoreductaseTransferase
HydrolaseLyase
IsomeraseLigase
12
EnvironmentalEffects
pHTemperatureDenature
EnzymesCharacteristics
Lower activation energyKey-Lock relation: active or catalytic site Catalyze reactions by concentrating substrate and binding correctly
13
Metabolic RegulationNature
Exceptionally complex and difficultAble to respond to environmental changes
SignificanceEssential for the cell to conserve energy and materialEssential for the cell to maintain metabolic balance
HowAmount of metabolites and enzymesActivity of enzymesFeedback inhibition
14
Metabolic ChannelingCompartmentationthe differential distribution of enzymes and cofactors among separate cell structures
Enzyme activityis coordinated through regulation of the transport of metabolites and coenzymes between cell compartments
15
Regulation Mechanisms
Central Dogma
16
Allosteric Regulation
17
Example
E. coli ACTase
18
Covalent Modification
Reversible addition or removal of a chemical group alters enzyme activity
19
Feedback (End Product) InhibitionMaintain appropriate concentration for each metabolitePacemaker enzyme or rate-determining reaction
