AMINO ACIDS AND PROTEINS Flashcards
Most abundant organic molecule in the HUMAN BODY
Proteins
Enantiomer of amino acids seen in the human body
L-isomer
An imino acid
Proline
AA with the smallest side chain, only achiral amino acid among the 20 AAs; Used in the first step of heme synthesis
Glycine
Accumulated AAs in maple syrup urine disease (MSUD)
Valine
Leucine
Isoleucine
AA with the largest side chain
Tryptophan
Known as the 21st AA
Selenocysteine
Known as the 22nd AA; restricted only in some methanogenic archaea and bacteria
Pyrrolysine
Only semi-essential AA
Arginine
Sulfur-containing amino acids
Cysteine
Methionine
AAs with aromatic structures (benzene rings)
Phenylalanine
Tyrosine
Tryptophan
Histidine
Most basic AA
Arginine
Most acidic AA
Aspartic acid
First ever sequenced protein
Insulin
First discovered hormone
Secretin
Most common secondary structure
Alpha-helix
Secondary structure seen in abnormal prion protein (PrP Sc) and Alzheimer disease histopathology
Beta-sheets
AAs that can disrupt the alpha- helix structure
Proline
Glycine
The only structure of proteins not affected by denaturation
Primary structure
Reading of amino acid sequences
From N-terminus (NH3 end) to
C-terminus (COOH end)
Most common form of hemoglobin after birth
Hemoglobin A1
Location of alpha-globin genes
Chromosome 16
Location of beta-globin genes
Chromosome 11
Defect in sickle cell disease
Glutamate → Valine
at the 6th position of the beta-globin
Defect in hemoglobin C disease
Glutamate → Lysine
at the 6th position of the beta-globin
Hemoglobin Bart composition
4 gamma-globin
Hemoglobin H composition
4 beta-globin
Oxygen dissociation curve of myoglobin
Hyperbolic
Oxygen dissociation curve of hemoglobin
Sigmoidal
Most abundant protein in the body
Collagen
Most common form of collagen in the body
Type I collagen
Type of collagen present in early wound repair
Type III collagen
Type of collagen in late wound repair
Type I collagen
Defective step of collagen synthesis encountered in scurvy
Hydroxylation step
Defective step of collagen synthesis encountered in osteogenesis imperfecta
Formation of triple helix
Defective step of collagen synthesis encountered in Menkes disease
Cross-linking step (dysfunction in copper- requiring lysyl oxidase)
Most common form of EDS
Hypermobility EDS
Most serious form of EDS
Vascular EDS
Most common type of collagen affected in EDS
Type III collagen
Defective type of collagen in dystrophic epidermolysis bullosa (DEB)
Type VII collagen
Defective structure in Marfan syndrome
Fibrillin
Triad of Marfan syndrome
Skeletal changes Aortic dilatation Upward and outward dislocation of the lens (vs downward and inward dislocation of the lens in homocystinuria)
Main cell that synthesizes antibodies or Igs
Plasma cells (derived from B cells)
Fragment of Ig containing the antigen-binding site
Fab
Fragment of Ig containing the complement-binding site and macrophage-binding site
Fc
Responsible for determining the isotype of class of Ig
Heavy chains
Most abundant light chain in humans
Kappa chain
Proteins containing light chains and can be found in the urine of patients with multiple myeloma
Bence-Jones protein
Most abundant Ig in the BODY (which includes mucous membranes)
IgA
Most abundant Ig in SERUM
IgG > IgA > IgM > IgD, IgE
Cleaves Ig into 3 parts
Papain
Cleaves Ig into 2 parts
Pepsin
Refers to the part of the ANTIGEN to which an antibody binds
Epitope
Refers to the part of the ANTIBODY that binds to the epitope of the antigen
Paratope