Proteins Flashcards
What does primary structure determine?
1 identity of protein
2 molecular structure
3 functions performed
4 molecular binding
Analytic processes used in the laboratory
Chromatography
Electrophoresis
Dye binding
Light absorbance
Properties of secondary structure
Strength
Flexibility
3 structures of secondary structure
a-helix
B-pleated sheet
Bend conformations or turns
It refers to overall shape or conformation of the protein molecule (known as the fold)
Tertiary structure
Results from interaction of side chains
Tertiary structure
What does tertiary structure determine?
Function
Physical and chemical properties of protein
What stabilizes tertiary structure?
Hydrophobic effect
Ionic attraction
Hydrogen bonds
Disulfide
Shape from interaction of more than one protein molecule
Quaternary structure
Forces that hold together quaternary structure
Non-covalent (H bonds, electrostatic interaction)
Lost of the native or naturally occurring folded structure
Denaturation
Denaturation can be accomplished by action of
Heat
Acid
Alkali
Enzymes
Contain peptide chains composed of only amino acids
Simple proteins
Functions of globular proteins
Transporters
Enzymes
Messengers
Characteristics of globular proteins
Symmetrical and soluble in water
Characteristics of fibrous proteins
Asymmetrical
Inert
With hydrophobic R groups
Examples of globular protein
Albumin
Hemoglobin
Immunoglobulin
Examples of fibrous protein
Troponin
Collagen
What are conjugated proteins?
Proteins that consist of a protein and prosthetic group
It defines the characteristics of the protein (conjugated protein)
Prosthetic group
Examples of conjugated proteins
Metalloprotein
Lipoprotein
Glycoprotein
Nucleoprotein
Examples of metalloproteins
Ferritin (iron)
Cerruloplasmin (copper)
Hemoglobin
Flavoprotein
Examples of lipoprotein
HDL
LDL
Examples of glycoprotein
Haptoglobin
a-antitrypsin
Example of nucleoprotein
Chromatin
What is the N content of serum proteins?
16%
Other term for prealbumin
Transthyretin
Characteristics and properties of protein
1 contain nitrogen atoms
2 can be positively or negatively charged
3 isoelectric point: number of positive = number of negative groups
4 (-) : pH>pI solution and (+) : pH<pI solution
5 solubility depends on the number and type of its amino acid and pH
6 molecular size : macromolecules with an average of 200-300 amino acids
7 synthesized in the liver (plasma proteins) and plasma cells (immunoglobulins)
8 catabolism : routes for converting proteins to free amino acids
Control protein synthesis
Thyroxine
GH
Insulin
Testosterone
Control protein catabolism
Glucagon
Cortisol
Degrades extracellular and intracellular proteins
Lysosomal pathway
Degrades extracellular proteins
Cytosolic pathway
Remove nitrogens from AA
Transaminations
Products of transamination
Ammonia
Ketoacids
Oxidized and converted to glucose or fat
Ketoacids
Converted to urea in hepatocytes and excreted in urine
Ammonia
