Amino Acids and Proteins Flashcards
pKa of amino acid carboxylic acid
~2.5
pKa of amino acid amino
~9.5
Aliphatic AAs
Gly, Ala, Leu, Ile, Val
Hydroxyl and Sulfhydrl Containing AAs
Ser, Thr, Tyr
Met, Cys, Sec
Acid AAs (and their amides)
Asp, Glu
Asn, Gln
Basic AAs
Arg, Lys, His
Aromatic AAs and Imino Acid
Phe, Tyr, Trp, His
Pro
Wavelength which aromatic amino acids absorb UV light
275-280 nm
Strongest chromophore amino acids
Tryptophan and tyrosine
Laber-Beer Law
A = e c l
e - molar absorptivity constant
c - concentration
l - path length
Angle between atoms on a peptide bond
120 degrees
Peptide Bond – trans or cis
trans configuration due to steric interference
Physiologically Active Peptides
Insulin, glucagon, oxytocin, vasopressin
Glutathione
Anti-oxidant preventing damage to cellular components from reactive oxygen species
Glutathione reducase
Reduces “disulfide bound glutathione dimer” (terminology?) to 2 glutathione
Glutathione peroxidase
Glutathione mediated reduction of hydrogen peroxide by NADPH
Functions of Proteins
Enzymes, hormones, storage prteins, transport proteins, structural proteins, protective proteins, contractile proteins
Flavoproteins (what is the prosthetic group?)
Flavin nucleotides
Chromoprotein (what is the prosthetic group?)
pigmented prosthetic group
Protein purification separating by charge
Ion Exchange Chromatography
Isoelectric Focusing
Electrophoresis
Protein purification separating by size
Dialysis and Ultracentrifugation
Gel Electrophoresis
Gel Filtration (size exclusion chromatography)
Protein purification separating by charge AND size
2D gel
Protein purification separating by specificity
affinity chromatography
Protein purification separating by polarity
Paper chromatography
Reverse-phase chromatography
Hydrophobic chromatography