PRELIM 02 - Proteins Flashcards
Are polymers of amino acids
Proteins
Are molecules that contains an amino, carboxyl, and side chain group
Amino acid
A chemical group that gives identity to the amino acid
Side chain group (R)
All amino acids, except __________ have at least one stereocenter and are achiral
Glycine
Molecules that contain both positive and negative charges
Zwitterion
Proton donor
Bronsted acid
Proton acceptor
Bronsted base
The pH at which the net charge of an amino acid/peptide is zero
Isoelectric pH (pl)
Is an amide bond between the α-carboxyl group of one amino acid and the α-amino group of another amino acid
Peptide bond
Molecules that are two or more amino acids linked by peptide bonds
Peptides
Are amino acids not or inadequately synthesized by the body; essential in the diet
Essential amino acids
Are amino acids that can be synthesized in the body; not required in the diet
Non-essential amino acids
Refers to the spatial arrangement of atoms in a protein
Conformation
The three-dimensional structure of a protein is called __________
Native conformation
Are proteins in any of their functional, folded conformation
Native proteins
4 levels of protein organization
Primary, Secondary, Tertiary, Quaternary
It refers to the sequence of amino acids in a polypeptide chain (Levels of protein organization)
Primary structure
It refers to the ordered 3D arrangements in localized regions of a polypeptide chain (Levels of protein organization)
Secondary structure
3 types of secondary structure of proteins
α-Helix, β-sheet, Random coil
Spiral structure; stabilized by intramolecular hydrogen bonds (Types of secondary structure of proteins)
α-Helix
Pitch of α-Helix
5.4 Angstrom
It is formed when 2 or more polypeptides line up side by side (Types of secondary structures of proteins)
β-sheet/β-pleated sheet
2 types of β-sheets/β-pleated sheets
Anti-parallel β-sheet, Parallel β-sheet
These are non-repetitive structures; an irregular or unique conformation (Types of secondary structures of proteins)
Random coils
Are structures that are combinations of α and β-strands
Supersecondary structures
4 examples of supersecondary structures
βαβ unit, αα unit, β-meander, Greek key
It refers to the three-dimensional conformation of the entire polypeptide (Levels of protein organization)
Tertiary structure
Are proteins composed of a polypeptide chain arranged in long strands or sheets
Fibrous proteins
2 examples of fibrous proteins
Collagen, Keratin
Are proteins composed of a polypeptide chain folded into compact, spherical structure
Globular proteins
2 examples of globular proteins
Enzymes, Hemoglobin
It refers to the spatial arrangement of polypeptide subunits (Levels of protein organization)
Quaternary structure
Quaternary structure with 2 subunits
Dimer
Quaternary structure with 3 subunits
Trimer
Quaternary structure with 4 subunits
Tetramer
2 examples of glucose homeostatic proteins; they control carbohydrate metabolism by binding on specific receptors
Insulin, Glucagon
Insulin and glucagon are synthesized at the __________
Pancreas
Insulin is synthesized at __________
β-cells
Glucagon is synthesized at __________
α-cells
Hormone of nutrient abundance; a protein hormone consisting of two amino acid chains linked by disulfide bonds
Insulin
3 major targets for insulin
Liver, Skeletal muscle, Adipose tissue
A 29-amino acid polypeptide hormone that is a potent hyperglycemic agent
Glucagon
Refers to the breakdown of glycogen to glucose
Glycogenolysis
Refers to the synthesis of glucose from lactic acid and non-carbohydrates
Gluconeogenesis
2 examples of hemeproteins
Hemoglobin, Myoglobin
Hemoglobin’s major role is __________
Oxygen transport
Myoglobin’s major role is __________
Oxygen storage
Tetramer of hemoglobin
α2β2
Other name for immunoglobulin; is a y-shaped molecule produced by B-cells during adaptive immune response
Antibodies
Immunoglobulin is composed of __________ subunits; __________ heavy chains and __________ light chains
4 subunits, 2 heavy chains, 2 light chains
Immunoglobulin is composed of: __________, __________, and __________
Constant regions, Variable regions, Hinge
5 antibody isotypes
IgM, IgA, IgD, IgG, IgE
The antibody which serves as protection for primary infections
IgM
The antibody that is commonly found in human secretions like tears, mucous, and saliva
IgA
The cell attached antibody which function is still under study
IgD
The most dominant antibody in humans; this antibody is responsible for secondary immune response
IgG
The antibody responsible for allergic reactions
IgE
It refers to the disruption of the protein conformation as well as its function
Denaturation