McMurry (Kap 19,4) - Peptides and proteins Flashcards
What are proteins and peptides (shorter chains of amino acids)?
Amino acid polymers.
What is the individual amino acid called in the protein/peptide?
A residue
What are the aminoacids linked together by?
Amide bonds/peptide bonds.
An amino group from one residue form an amide bond (NH2) with the carboxyl of a second residue. The amino group from the second residue form an amid bond with the carboxyl of a third and so on.
(see example page 689) - water is formed as a byproduct.
Do you get the same dipeptide if two aminoacids are linked together by (serine - Alanine) or (Alanine - Serine)?
NO, two different result.
The long sequence of N-CH-CO atoms make up a contonuise chain called the proteins backbone.
True.
Peptides are written with the N terminal amino acid (free NH3+ group) and the C-terminal amino acid (free CO2- group) on which side?
The N terminal on the left, and the C terminal on the right.
Are the names of the dipeptide said out long or shortened?
Shortened using the table 19.1
What is the amide bonds geometry that links the different amino acids together ?
The amide bond is planar and the N-H is oriented 180 degrees to the C=O.
What is a second kind of a covalent bonding that occurs in peptides?
the disulfide linkage (RS - SR) - between two cystein residues. (page 691)
What is the diffeence between the disulfide linkae and the disulfide bond/bridge?
The disulfide bridge is a bond between cystein redisues in the same chains - they are not linked together because they are besides each other, they are further away from each other in the chain.
It is a disulfide bond between them in the chain, to form a loop (see page 691).
