BCH-Week 2 Flashcards
How is the peptide bond formed betweeen two amino acids?
by condensation reaction where there is nucelophilic attack by amino group of one amino acid on the elctrophilic carboxyl group of another amino acid which releases water and that bond can be broken by hydroysis(addition of water)
What is the stereochemistry of amino acids?
they all are chiral except fro glycine, they are also enantiomeres of each other
What is the difference between essential and nonessential amino acids
essential amino acids means need to be obtained from our diet since they arent made in our body while nonessential means they can be synthesized in our body even if not gained from our diet since they can be made from other amino acids like glutamine from glutamic acid
Which amino acids has teh label of limino
proline because its amino group is part of the R group of the amino acid
Since amino acids are enantiomers of each other, how come we only see L-isomer amino acids and not both, L-isomer and D-isomer
that is because the L-isomer are better at binding with other amino acids and interacting with other molecules
What are the different types of noncovalent interactions that occur between amino acids in polypeptide
hydrophilic interactions between polar r groups and water
hydrogen bonding
salt bridge between postivily and negatively charged amino acids
hydrohpobic interaction
How does a disulfide bond form and is it a covalent or noncovalent interaction
disulfide bond occur between the sulfurs of teh two cysteine amino acids
it is a redox reaction where oxidizing the two cysteine amino acids make the disulfide bond forming cystine and the reduction of cystine will break the disulfide bond and result in two seperate cysteine amino acids
What is the enzyme that catalyzes teh formation of disulfide bond
PDI, protein disulfide isomerase
What are post translational modifications
addition of removing of functional groups after formation of the polypeptide chain which can change teh structure of protein and disulfide bond is type of PTM
What are some types of PTM
phosphorylation- adds or remove phosphate groups
ubiquitation- marks protein fro degradation
glycosylation- adding sugar to protein
acteyl, methyl, hydroxyl, and carboxyl
Amino acid metabolism
making other types of molecules from amino acids liek hormones and the nonessential amino acids
What are types of amino acid mutation
silent- doesn’t affect primary sequence since it codes teh same amino acids
nonconservative - amino acid is changed to another one with different properties so primary sequence is greatly changed
conservative- the amino acid is changed to one with same characteristics so protein’s structure doesn’t change
What is teh difference between protonation and deprotonation
protonation means it takes H+
deprotonation means it gives the H+
match the following:
1-protonated
2-deprotonated
a- pH<pKa>pKa</pKa>
1- a
2-b
What type of noncovalent interactions are influenced by pH
H-bonding and salt bridges as these two depend on charges and lone pairs
