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Biochemistry UCI
Steele
44
Medical
Graduate
08/15/2007

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Term
Drugs having effect on proteins
Definition
1.Gleevec - CML Cancer Drug, GF Inhibitor for WBC
2.Herceptin-HER2 GF inhibitor
3.Celebrex-COX Inhibitor Arthritis
4.Cialis-Guanylate Cyclase and cGMP
5.Prempro-Estrogen mimic
Term
Drugs that are proteins
Definition
1.Humulin-rDNA insulin from e. coli
2.Herceptin
3.Epogen-Stimulate RBC production
4.BeneFIX-Coagulation Factor IX recombinant
5.Neumega-IL-11 platelet production
Term
Protein Trivia
Definition
1.20,488 genes for diff. proteins
2.
Term
Proteomics
Definition
Deermination of structure, function, interaction, expression, location, modifications, timing of proteins to define tissue, organ, organ system, organism.
Term
Recognitive Proteins
Definition
Majority of Proteins
1.Enzymes
2.Igs
3.Receptors
4.Transcription Factors
5. Channels
Term
Structural Proteins
Definition
Provide Structure and contribute majority of bulk of an organism
1. Skeletal
2.Transient structures (Fibrinogen in blod clots)
3.Cytoskeleton
4.ECM
5.Contractile structures in muscle
Term
Some size considerations
Definition
C-H bond 10^-10m
Molecules 1-10nm
Cell 1um or 1,000nm

Time in milli and micro seconds
Term
Protein Org.
Definition
1.Primary: covalently bonded amino acid sequence
2.Secondary: H-bonded repetitive structures
3.Tertiary: Spatial Interactions including primary and secondary
4.Quarternary: Multiple polypeptide sub-units (homo and hetero)
Term
Amino Acids
Definition
20 used in human proteins, in "L" form, all same basic structure except proline (cyclic), encoded by three letter DNA code (3bp = 1aa).
Term
Special group AA's
Definition
1.Basic-Argenine, Lysine, Histidine
2.Acidic-Glutamate, Aspartate
3.Sulfur-Cysteine(S-S bonding), Methionine (start codon)
4.Phosphorylatable-Tyrosine, Serine, and Threonine
Term
Peptide Bond
Definition
Most are in trans formation
Phi N & alpha-C (-60degrees in helices)
Psi alpha-C & CO (-60degrees in helices)
Condensation to form, Hydrolysis to break
Term
Sequence Determination
Definition
1.Edmann degradation Phenylthioisocyanate label N-term, acid, chroma., repeat
2.Sanger Method-DNA sequencing
Term
Secondary Structure
Definition
1.Helices: alpha hellix most common
2.Beta Pleated Sheets: parallel and anti-parallel
3.Beta Turns
Term
Alpha Helix
Definition
Phi and Psi both at -60 degrees
H-bonds between peptide backbone CO and NH 4aa apart.
right handed helices

Alpha coiled coil such as keratin

Used to span across cell membrane
Term
Beta Pleated Sheets
Definition
parallel
anti-parallel
mixed

H-bonding of peptide backbone
Term
Beta Turns
Definition
1.Surface of proteins
2.site for glycosylation
3.Immuno recognition
4.Predictable
Term
Tertiary Structure
Definition
Stabilized by weak bonding
R groups are major players
Not predictable
dictated by primary sequence
Term
Tertiary Structure
Definition
Stabilized by weak bonding
R groups are major players
Not predictable
dictated by primary sequence
Term
Protein Folding
Definition
1.Globular
2.Driven by burying hydrophobic regions
3.Surface residues are polar
4.Charge pairs only when no water
5.Pi Stacks: aromatic R groups stabilize
6.Key positions are very specific in R group
7.Native Conformation: lowest energy form
Term
Protein Folding (cont.)
and Diseases
Definition
Chaperones and Chaperonins help keep proteins from mis-folding and sticking in wrong ways and sites.
1.Creutzfeldt-Jakob (madcow, scrapie)
2.Alzheimers
Term
Prions
Definition
Misfolded protein is template for ther proteins to misfold and accumulate into amyloid plaques. These are infectious.
Term
Protein Domains
Definition
1.Folds on own
2.Secondary structure connected by loops
3.Own Hydrophobic core
4.Ind. funtional and structural property

Examples are proteins that have binding domains, kinase domains, etc.
Term
Protein Motifs
Definition
Units within domains
Ex:1)GXGXPhiG: Binds PO3 of ATP
2)DFG: coordinates Mg binding to PO3 of ATP
Term
Protein Covalent Bonding
Definition
Disulfide Linkages: Cys-Cys sulfur groups bind proteins to themsleves, to other proteins, and more

Immunoglobulins and Insulin are good examples
Term
Protein Structure Determination
Definition
1.X-Ray Crystallography: crystallize proteins, shoot x-rays, measure diffraction pattern, mathematically workout structure
2.NMR: Protein in solution, complex spectral data, only up to 900aa
Term
Protein Properties
Definition
1.Size
2.Shape
3.Charge
4.Location
Term
Protein Size
Definition
50,000-70,000 Dalton
avg. amino acid is 100 Da
avg. protein is 500 to 700 aa's
Super large ex. dystrophin is 3685. Doesn't get translated before cell cycles often.
Term
Protein Shape
Definition
1.Globular - dominant type
(e.g.enzymes)
2.Structural - elongated (e.g. collagen, elastin, keratin)
Term
Collagen
Definition
1. 10 isoforms
2. 3 polypeptides (2 alpha and 1 beta chains) twisted in rt. handed triple helix
3. those fibers form fibrils
4. Glycine is major constituite
5.Starts folding in ER at COOH end
6. Gly-X(proline)-Y(hydroxyproline)
Term
Collagen Disease
Definition
1.Osteogenesis Imperfecta: Gly is replaced destabilizeng collagen. If close to COOH the problem is worse. Dominantly inherited (25% spontaneous)
2. Scurvy
Term
Transmembrane Proteins
Definition
1.Type I (N-terminus EC) Type II (C-terminus EC)
2.Multiple passes
3.Glyosylattion and disulfide bonds EC
4.Thiol, Phosphorylation IC
Term
Surface Proteins
Definition
Extrinsic to membrane
Lipophilic anchors
Term
Protein Charge
Definition
1.Charged R groups: Glu, Asp, His, Arg,Lys
2.N and C termini
3.Modifications (PO3-)
4.Metal Ions
Term
Ka and pKa
Definition
[H][A]/[HA]

equilibrium constant

pKa is pH at which R group is charged
Term
pI
Definition
Isoelectric Point - Point at which protein has no net charge.
Used in Isoelectric focusing
Term
Protein Localization and Targeting Sequences
Definition
1.Nucleus: KKXK or (K/R)2-x10-12-(K/R)
2.Peroxisome: SKL-COO terminus
3.Mitochndria: N-terminal amphipathic helix
4.ER: KDEL-COO terminus
Term
Protein Glycosylation
Definition
1.N-linked: sugar on N of Asp
2.O-linked: sugar on OH of Ser or Thr
Term
Mitochondrial Localization of Proteins
Definition
Two Membranes to cross.

Tom on outer and Tim on inner.

Folded inside Mitos.

No Sugars, no S-S, free N-terminus when targeting sequence is clipped (unlike cytosolic proteins)
Term
Protein harvesting and characterization
Definition
1.Crude (ppt and dialysis)
2.Ion-exchange (charge)
3.Gel Filtration (size)
4.Absorption (hydrophobicity)
5.Affinity (Interaction with other molecules like Ig, Metals
6.Preparative electrophoresis (SDS-PAGE)
Term
Protein Sequence Comparison
Definition
1.Same function across species, similar sequences
2.Tertiary structure may be more conserved than primary sequence
3.Convergent evolution
Term
Protein Families
Definition
Orthologues: Same protein in different species
Paralogues: Gene duplication within same organism
Term
Mutations
Definition
Hb in Sickle Cell is a point mutation, E is changed to V
Term
Allozyme vs Isozyme
Definition
Allo-form of protein begat by alleles of same gene
Iso-proteins from different genes, but catalyze same reaction (kinetically different often)

Isozyme example: LDH is tetramer (homo and hetero) in muscle(M)and heart(H) are isozymes. H has higher affinity for S than M. H inhibited by pyruvate, not M. M functions in anaerobic enviro., H in aerobic. LDH profile changes over time.
Term
More isozymes in MI
Definition
Creatine Kinase-2: activity peaks at 24hr after MI
LDH peaks at 36-40hr post MI
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