protein cleavage - week 2 Flashcards
what is protein cleavage ?
the process by which specific peptide bonds between amino acid residues are hydrolysed
What performs the leakage of peptide bonds?
proteins known as proteases
Why is protein cleavage important?
- protein degradation
. recycling, digestion - post-translational porcessing
. N-terminal met, signal sequences. precursors
Proteins fall into broad families that share common characteristics. name examples
- metalloproteases eg. carboxypeptidase A
- Serine proteases eg. Chymotrypsin
- Aspartyl proteases eg. HIV protease
What is CPA 1 and where is it found?
- digestive enzyme found in the gut
Describe CPA 1
- member of the family of proteins called metalloprpteases
- contains zinc
What do all metalloproteases have?
metal ion in active site of enzyme
What does CPA do?
- cleaves off last C-terminal residues form peptide chain
- functions best when residue Is aliphatic (val, leu, ill, ala)
where is chymotrypsin found?
digestive enzyme in the gut
What family is chymotrypsin a member of?
serine protease
what do all serine proteases have?
a critical serine residue in active site
What does chymotrypsin do?
cleaves peptide bond on the carboxyl side of aromatic or large hydrophobic residues
What is the role of HIV protease?
- cleave itself out of a large polypeptide chain produced from oral genetic material
- proceed to chop up remaining bits of polypeptide into functional proteins
- viral réplication
What family is HIV protease a member of?
aspartyl protease
What does HIV protease have in its active site?
critical aspartic acid