Amino Acids (L1, L2) Flashcards
Which reaction serves as a mechanism for the transport of carbon dioxide from tissues to lung by hemoglobin?
The addition of carbon dioxide to the alpha amino group of amino acids, forming carbamino compounds.
What ions does Bieuret reagent contain?
Cupric ions in alkaline medium
Why does Bieuret reaction give purple/violet colour?
Due to the presence of protein/peptides & the colour is due to the formation of at least 2 peptide bonds (nitrogen)
Millons reaction?
Red colored mass for tyrosine
Aldehyde reaction?
Violet ring for tryptophan
Sakaguchi test?
Red color for guanidine group of arginine
Lead sulphide test?
Brown color for sulfur containing amino acids
If pH of a solution is less than its IEP, the amino acid or protein will be?
Positively charged.
Stability of proteins in solution depends on?
-charge
-hydration
What is salting out?
It is a protein precipitation method by which the hydration shell of protein is removed using a neutral salt such as ammonium sulphate or sodium sulphate in the protein solution.
Higher the molecular weight of the protein, the salt required for precipitation is (less/more)?
Lesser.
For example,
Albumin requires full saturation of ammonium sulfate
Globulins require only half saturation of ammonium sulfate
Explain the disinfectant effect of alcohol.
Alcohol is an organic solvent which lowers the dielectric constant of the medium and favors protein precipitation. When it is added to the protein solution, water molecules available for proteins are reduced and precipitation occurs.
What is the primary structure of amino acids?
Number and arrangement of amino acids.
What is the secondary structure of proteins?
Folded structures within the chain of amino acids. They result from H bonds between carbonyl O and amide H of 2 amino acids.
Two types; alpha helices and beta pleated sheets.
What is tertiary structure of proteins?
It’s the overall shape of the protein. Determined by; disfulphide bonds, H bonds, salt bridges, hydrophobic interactions.
