Hemoglobin and myoglobin are the two oxygen-binding proteins present in large multicellular organisms.
Hemoglobin transports oxygen in the blood and is located in the erythrocytes; while Myoglobin stores the oxygen in the muscles.
~ Distribution ~
HB : In Blood
MB : In muscles
~ structure ~
HB : 4 polypeptide chains ( 4 units ) = 2 alpha + 2 beta
MB : single polypeptide chain ( 1 unit ) = similar to the beta unit of hemoglobin
~ Oxygen capacity ~
HB : four Oxygen molecules (4 O2 )
MB : One Oxygen molecule ( 1 O2 )
~ Affinity for Oxygen ~
HB : low affinity to Oxygen , and it increases gradually with the increase in O2 concentration
MB : High affinity to oxygen even in very low O2 concentration
.:: Hint ::.
Fetal hemoglobin consists also of 4 units = 2 alpha and 2 Gamma ” Not Beta ”
fetal Hemoglobin ” HBF ” Has higher affinity for O2 than Adults hemoglobin “HBA”
which promotes the transfer of O2 from the maternal circulation ( Mother ) to the fetal circulation ( baby ) .
” BIOS instant notes in biochemisrty “
” Biochemisrty text book by Garrett & Grisham “