Biochem Globin Family part 1

which was the first protein to be crystaillized and how

hemoglobin via xray

-learned to measure mass and first to link disease

hemeglobin was studied how

ultracentriguation

what did we learned from Hb

how single point mutation can cuase things

-also its O2 binding changes after each O2 is bounf

Myoglobin

stores o2 In muscles

-helps with o2 solublity in tissues and helps speed it up

myoglobin in different anaimsl

deep diving animals can carry 10x more Mb

Hemeglobin is made of

2 a and 2b

Hb does hwat

brings o2 from lungs to tissues

-helpsw tih plasma solubility by boositing it about 100x

O2 carrier of Cu

hemocyanin

Hemerythrin

lacks heme

how many O2 can heme bind to

1 heme and Myo and Hb has only 1 heme group

Heme is what strucutre

heteocyclic ring strucutre

Heme has what

iron

what state must the iron be in

Fe2+ ferrous state to bind O2

F3 doesnt work and needs to be reduced

LEO

Loss of e- is oxidation

GER

gain of e is reduction

When hemoglobin is carrying oxygen (oxyhemoglobin)

the light has 2peaks at 540 and 580 nm

-gives arterial blood red hue

Deoxyhemoglobin shifts

has only 1 shift and gives veinous blood looks darker blue

Where does Hb get its color

Red color from the energy different between irons D orbital

what config is Fe2 in

Fe2 is in low spin d6 config

where to look to see how much O2 is bound to Hb

Measuring absorbance around 578 nm i

Methemoglin

when He changes fro f2 TO fE3

-cannot bind O2 and blood looks brown

what is used to reduce methemglobin brown color

ascorbic acid

What changes methemoglin back into working Hb

enzyme called methemoglobin

What does Kd show

how tightly myoglobin holds onto oxygen.

Small kd means

more tightly bound O2 and Mb

Larger kd means

more weakber between o2 and Mb

The fractional saturation (Y O₂) tells you

what fraction of myoglobin molecules have oxygen attached.

What does YO2 depend of

partial pressure of oxygen (pO₂) and P50,

P50

THE o2 PRESSURE WHERE HALD THE Mb is filled

when Po2= P50

half the Mb is oxygenated

P50 gives you a measure of

affinity

lower P50 means

higher O2 affinity

-proteins can bind O2 easier

Mb P50 is

2.8torr-which is low

- myoglobin has high affinity

P50 of aterial blood

100 tor

Venous blood P50

30 tor

Hb P50 is

26 torr and makes it easy to release O2 faster

Hill equation waht is the enzyme

Hb

Hill equation ligand is

O2

The Hill equation is often used to describe

cooperative binding

The Hiid coefficent n is greatest than 1 means

binding 1 liagnd makes it easier for next one to bind

Fractioanl saturation Ys

fraction of all avaliable binding sites that have a ligand attached

Hill coeffecient n=1

each site binds indept

Hill coeffiecent n is greater

binding is easier with each next one

Hill coeffecient n is less than 1

negative cooperativity binding become harder

Hb shwos what type of cooperativtiy

positive since each binding of O2 gets easier than the last and by the fourth its 100x easier to bind than the first

Hb energy different in affinity is

11.4kj/mol

Hb O2 leaving influcnese other how

when one o2 leaves the others are more likely to be released

which lets go of O2 more easily

Hb since Mb is a storage molecule

What does globin help with Fe

helps keep it in the fE2 state

Where is iron binded on heme

the irons 5th site is anchored to a Hisitide while O2 binds at 6th site on opposite side

What happens to iron with globin

can become oxidzed to FE3 and cannot bind O2