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SET 9 - Professor Venkatesh Shanbhag
Biochemistry/Lab (CHEM 3650)
Nova Southeastern University
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SET 9
cooperative effect:Enhanced activity resulting from cooperation between subunits of an allosteric molecule
heme:The prosthetic group of myoglobin and hemoglobin as well as other proteins
What consists of an organic constituent, protoporphyrin, and an iron atom? heme protoporphyrin: An organic constituent of the heme prosthetic group What consists of four pyrrole rings joined by methine bridges and contains various side chains? protoporphyrin proximal histidine:The residue occupying the fifth coordination site to which iron can bind in hemoglobin and myoglobin distal histidine: A histidine located near the heme group in myoglobin and hemoglobin that helps maintain the heme iron in the Fe2+ oxidation state and inhibits carbon monoxide binding.
__________ _________ is on the opposite side of the heme from the proximal histidine histidine
α subunit: A subunit of human adult hemoglobin A, which consists of four subunits: two α subunits and twoβsubunits
β subunit:A subunit of human adult hemoglobin A, which consists of four subunits: two α subunits and two βsubunits αβ dimer: In hemoglobin, consists of an α subunit and a βsubunit. The three-dimensional structure of hemoglobin consists of a pair of identical αβ dimers (α1β1 and α2β2) that associate to form the ___________ ______________ hemoglobin tetramer 2,3-bisphosphoglycerate (2,3-BPG): An allosteric regulator of oxygen binding by hemoglobin. Also called 2,3-diphosphoglycerate (2,3-DPG). 2,3-bisphosphoglycerate (2,3-BPG) fetal hemoglobin: A tetrameric molecule comprising two α subunits and two γ subunits. The γ subunit of fetal hemoglobin is ___% identical in amino acid sequence with the adult hemoglobin βsubunit. 72 Bohr effect: The observation made by Christian Bohr that H+ and CO2 promote the release of oxygen from oxyhemoglobin.
Carbamate:
Heme consists of protoporphyrin, an organic component with four linked _________ rings, and acentral _____ ion in the ferrous (Fe2+) state. pyrrole;iron Myoglobin is a largely __-helical protein that binds the prosthetic group heme.α
The iron ion of a heme group is coordinated to the side chain of a histidine residue in myoglobin,referred to as the _____ ___________. proximal histidine In a heme group, one of the oxygen atoms in O2 binds to an _____ ______________ site on the iron ion. open coordination Because of _______ __________ __________ from the iron ion to the oxygen atom in a heme group, the iron ion moves into the plane of the porphyrin on oxygen binding. partial electron transfer Hemoglobin Binds Oxygen _______________Cooperatively
Hemoglobin consists of four polypeptide chains: two α chains and two β chains. Each of the chains in Hemoglobin is similar in amino acid sequence to ____________ and folds into a similar three-dimensional structure. myoglobin The hemoglobin tetramer is best described as a pair of ____________.
αβdimers The oxygen-binding curve for hemoglobin has an "S"-like, or sigmoidal, shape, indicating ... that the oxygen binding is cooperative. ________________ oxygen binding and release significantly increase the efficiency of oxygen transport. Cooperative The quaternary structure of hemoglobin changes on ___________ ___________ binding
The two αβ dimers rotate by approximately ___ degrees with respect to each other in the transition from the T to the R state. 15 Structural changes at the iron sites in response to oxygen binding are transmitted to the interfacebetween ___ ________, influencing the T-to-R equilibrium αβ dimers An _________________ Regulator Determines the Oxygen Affinity of Hemoglobin Allosteric Red blood cells contain ________________________ in concentrations approximately equal to that for hemoglobin. 2,3-bisphosphoglycerate 2,3-BPG binds tightly to the T state but not to the R state, stabilizing the T state and __________the oxygen affinity of hemoglobin. lowering
Because hydrogen ions and carbon dioxide are produced in rapidly metabolizing tissues, the ______ _______ helps deliver oxygen to sites where it is most needed. Bohr effect _____________ in Genes Encoding Hemoglobin Subunits Can Result in Disease Mutations The fibers formed as a result of a hydrophobic patch forming distorts red blood cells into _______ shapes. sickle Sickle-cell disease is caused by a mutation in the β chain of hemoglobin that substit_________ residue for a glutamate residue. utes a valine ___- disease was the first disease to be associated with a change in the amino acid sequence of a protein. Sickle-cell As a result of a val residue being sunstituted for a glu residue, a ______________ _________ forms on the surface of deoxy (T-state) hemoglobin that leads to the formation of fibrous polymers. hydrophobic patch __________________ are diseases caused by the reduced production of either the α or the βchain, yielding hemoglobin tetramers that contain only one type of hemoglobin chain. Thalassemias Hemoglobin molecules like those in thalassemias are characterized by poor oxygen ______________ and ____ solubility, leading to the destruction of red blood cells in the course of their development.
release;low cooperative effect: Enhanced activity resulting from cooperation between subunits of an allosteric molecule. heme: The prosthetic group of myoglobin and hemoglobin as well as other proteins; consists of an organic constituent, protoporphyrin, and an iron atom.
protoporphyrin:An organic constituent of the heme prosthetic group; consists of four pyrrole rings joined by methine bridges and contains various side chains. proximal histidine: The residue occupying the fifth coordination site to which iron can bind in hemoglobin and myoglobin
distal histidine: A histidine located near the heme group in myoglobin and hemoglobin that helps maintain the heme iron in the Fe2+ oxidation state and inhibits carbon monoxide binding. It is on the opposite side of the heme from the proximal histidine. α subunit: A subunit of human adult hemoglobin A, which consists of four subunits: two α subunits and twoβsubunits.
β subunit:A subunit of human adult hemoglobin A, which consists of four subunits: two α subunits and two βsubunits. αβ dimer:
SET 9 - Professor Venkatesh Shanbhag
Course: Biochemistry/Lab (CHEM 3650)
University: Nova Southeastern University
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