CHMA 2002 - Module 2E: Structure and function of a protein

The right side and systematic veins carry

oxygen poor and cO2 rich blood

Systematic arteries and the left side carry

oxygen rich and CO2 poor blood

Hb is

hemoglobin

Mb is

myoglobin

myoglobin is a __________ protein

monomeric

Myoglobin is a ___ structure

tertiary (3)

Myoglobin is conjugated because it

has a non-protein component called Heme (in red)

myoglobin facilitates the diffusion of oxygen from

blood to muscle

myoglobin serves to

store O2

Hemoglobin is a _____________ protein with a ___________ structure

tetrameric , quaternary

hemoglobin serves as an

O2 carrier

Hemoglobin supplies oxygen from

the lungs to Mb in muscle

both Mb and Hb can

selectively and reversibly bind O2

the stability of Mb is from

non-covalent, hydrophobic core

Between Mb and Hb, which is a carrier protein and which is a storage protein?

Hb=carrier

Mb=storage

Myoglobin is a ______________protein

monomeric

Hemoglobin is a ____________ protein

tetrameric

Mb and Hb have ____________ and ______________ binding to O2

selective and reversible

myoglobin is a bundle of

8 alpha helices

Myoglobin is rendered stable due to its

hydrophobic core

The prosthetic heme group in myoglobin is located in the

hydrophobic core between E and F helices

To reversibly bind oxygen to heme, an electron is temporarily transferred from

Fe2+ to O2

Hb has how many subunits, each of which contain a...

4, heme group

blue is

deoxy

red is

oxy

oxygenation occurs with ____________ bonding

non-covalent

What shape is the binding curve of Hb

sigmoidal

what shape is the binding curve of Mb

hyperbolic

T/F: The subunits of Hb are identical to Mb

False, similar but not identical. Mb has eight alpha helices and Hb subunits only have 7

The sigmoidal shape of binding curves in Hb indicates

binding of one O2 molecule to a heme group, facilitating faster binding of O2 to the other heme groups of Hb

The phenomenon of the sigmoidal shape of binding curves in Hb is called

positive cooperativity of binding

What is the reason for positive cooperativity of binding in Hb

Allosteric regulation:

The conformational changes occurred in the quaternary structure of Hb

When P50 is lower,

affinity to oxygen to these molecules is higher

P50 compares

binding affinities