proteins and amino acids - 3 Flashcards
whats the role of haemoglobin and where is it found ?
to transport oxgyen and found in bloodstream
whats the proper name for RBC ?
erthrocytes
whats the structure of haemoglobin ?
2 beta sheet and 2 alpha helix with hame prosthetic group for each subunit so 4 heme groups per haemoglobin molecule.
what gives haeme its red colour ?
has conjugated system and it absorbs light in the visible spectrum , hence red colour
what does heame group do to oxygen ?
accepts and donates oxygen
what type of curve is produced by haemoglobin and why ?
A sigmoidal curve as the ratio of binding oxygen is not equal
what occurs if theirs a small increase in oxygen concentration ?
allows Hb to bind its maximum oxygen
small decrease in oxygen ?
allows Hb to off load all oxygen
how is the mechanism of Hb described and why ?
allosteric as the 4 proteoheame groups are not in direct contact with each other. A change can cause an alteration in the ability to bind or release oxygen .
simply with planes describe what occurs when oxygen binds to haemoglobin ?
oxygen binds and fe now has 6 ligands instead of 5. This pulls Fe into ring plane and histidine pulled closer
what type of enzyme is carboxypeptidase A and B
a digestive enzyme
whats the role of carboxypeptidase A ?
removes aromatic amino acids from the c terminal ends of proteins
role of carboxypeptidase B
this removes amino acids from the positively charged side chains
what atom is bound to each molecule ?
a zinc atom
what occurs to the zinc atom in carboxypeptidase when the substrate binds ?
the Zn atom partially complexes with the oxygen from the substrate carbonyl group. The Zn then polarises the C-o bond and this makes the carbonyl carbon susceptible to nucleophilic attack.
