Nature's tools Proteins and Enzymes
- Created by: jessica
- Created on: 10-12-12 18:42
View mindmap
- Nature's tools Proteins and Enzymes
- Amino Acids
- Are chiral have 2 mirror image forms-D and L
- Only L isomers used to make proteins
- Are zwitterions
- 20 different amino acids
- R groups make them different
- Side groups with just C-H are non polar and hydrophobic
- Side groups with N-H are polar and hydrophilic
- R groups make them different
- form peptide bonds by carboxyl group of one amino acid joining to amino group of another
- Are chiral have 2 mirror image forms-D and L
- Protein Structure
- Amino acids joining together forming polypeptide chains
- Sequence of amino acids determines structure
- mass measured in daltons
- most proteins are trans configuration
- Primary, Secondary, Tertiary and Quarternary Structure
- tertiary
- Reverse turns turns, Beta turns, hairpin turns, omega loops further fold the structure
- Secondary is when alpha helix, Beta sheets and strands form by folding of the polypeptide chain and held in place by hydrogen bonding
- Right handed helices are energetically more favourable
- Beta Sheets can be parallel or antiparallel
- Quarternary
- is the spatial arrangement of subunits and the nature of their interactions
- Primary is the initial sequence
- tertiary
- Amino acids joining together forming polypeptide chains
- Enzymes
- Biological catalysts
- Competitive non competitve and uncompetitve inhibitors
- uncompetitive binds to enzyme substrate complex effecting both Vmax and KM
- Competitive similar to substrate shape, doesnt affect Vmax but increases Km
- Non competitive binds to different binding site preventing enzymesubstrate complex forming, decreases Vmax, Km stays the same
- Arrhenius equation K=A-exp-Ea/RT
- Rate constants changes Km and Vmax values
- decrease deltaG (activation energy)
- Active sites are 3D clefts/crevices that create microenvironments
- Km/Kcat is a measure of catalytic efficiency
- Activity regulated by allosteric control,multiple forms of enzyme,reversible covalent modification, proteolytic activation, controlling amount of enzyme present
- Protein determination and purification techniques
- Purification methods
- Salting out, Dialysis, Gel-filtration chromatography, ion exchange chromatography, High pressure liquid chromatography
- Salting out-fractionates proteins due to different solubilities
- Dialysis-separates proteins and small molecules through semi permeable membrane in a buffer solution
- Gel filtration Chromatography-sample applied to top of column with porous beads small and large molecules take different routes through the column
- Ion exchange chromatography-proteins separated on basis of their net charge
- High pressure liquid chromatography is an enhanced version of column technique
- Purification level is the measure of increase in purity and obtained by dividing specific activity
- Salting out, Dialysis, Gel-filtration chromatography, ion exchange chromatography, High pressure liquid chromatography
- 3D structure determined by X ray crystallography and NMR Spectroscopy
- X ray crystallography gives atomic detail
- NMR Spectroscopy shows structures of proteins in solution
- Purification methods
- Lipids and Cell Membranes
- lipids serve as fuel molecules, energy stores, signal molecules messengers in in signal transduction pathways, components of membranes
- fatty acids are key components of lipids
- 3 main types are glycolipids, phosholipids, cholesterol
- lipids are water insoluble biomolecules that are highly soluble in organic solvents
- membrane lipids have both hydrophobic and hydrophilic moiety
- Fatty Acid Metabolism
- Fatty acids oxidised in peroxisomes
- Degradation is an oxidative process
- Epinephrine and glucagon induce lipolysis
- Fatty acids stored as triglycerides
- fatty acids synthase used to synthesize fatty acids in the cytoplasm
- Amino Acids
Comments
No comments have yet been made