Flashcards in Hemoglobin Deck (57)
Where is myoglobin found
found in muscle for oxygen storage
Single ferous _____- containng heme prosthetic group in protective hydrophobic pocket binds oxygen
If oxidized to ferric (Fe+++)
it binds H20
what is myoglobins conformation stabilized by
Posterior 93 His (proximal) binds:
Distal His provides ___ ____ for unfavorable interactions
steric hindrance (CO)
What is a heme
4 pyrrole ring structures linked by methene bridges= porphyrin ring
When you add specific side groups to a heme its called:
A heme is not considered a heme until you add
Fe++ = heme
Where is heme found
oxygen transporter, and storage proteins and cytochromes
Myoglobin has ____ alpha helical conformation
75% (8 regions)
Myoglobins saturation curve is ____ and is indicative of its function.
hyperbolic; store oxygen until its critically needed
Hematopoietic stem cell directed to erythroid lineage by the hormone
Hemoglobin relies on ___ and ___ for energy
glucose and glycolysis
Small ___shape allows passage through capillaries
Hemoglobin is found in ____ for ____ transport.
Hemoglobin is a tetramer that has 2 ___chains and 2 ___chains. Thus Hb has a quaternary structure and exhibits _____
alpha; beta; cooperativity
What are the similarities between Mb and Hb
1. Each has 8 alpha helical regions connected by beta turns.
2. Heme prosthetic group
3. Distal and proximal histidines
Hemoglobin is designed to deliver oxygen :
all the time; therefore it has a sigmoidal curve
Myoglobin delivers oxygen only when partial pressure of oxygen is:
low; only delivers when need; therefore the curve is hyperbolic
What is the embryonic Hb like
zeta and epsilon chains
What is fetal Hb like
Adult alpha and fetal Beta like (gamma) are expressed during the 2nd and 3rd trimesters.
What is the adult hemoglobin like
2 alpha 2 beta (after 3 months of birth)
Hb conformation and oxygen affinity are dependent on 4 environmental variables:
4. 2,3 bisphospho-glycerate concentration
What is the Bohr effect
High [H] (low pH), high pC02, and high [2,3 BPG] lower oxygen affinity and shift oxygen saturation curve to the RIGHT --> Enhances delivery of oxygen to metabolically active tissues where C02 and H+ are accumulating
High ____ levels such as those in lung capillaries favors oxygen binding and shifts oxygen saturation curve to the ____
pO2 ; left
What is CADET, face RIGHT
O2 saturation curve shift to the right and inc O2 delivery in response to increases in:
3. 2, 3 BPG
Acidic conditions favor ___ ____ between chains to stabilize the deoxy or ___ form of hemoglobin. Oxygenation breaks these bonds, and converts the tetramer to the oxy or relaxed (R) form.
salt bridges; T.
___ serves as an acid sensor. Once protonated, it can participate in ionic bonds.