Analisis

Chapter 5
Heme: protein bound prostatic group. Consists of a complex organic ring structure protoporphyrin.
Porphyrin ring: the iron atom has six coordination binds four to nitrogen atoms that arepart of the ring and are perpendicular to the porphyrin. The coordinated nitrogen atoms (which have an electron donating character) help prevent conversion of the heme iron to the ferric Fe3+ state.When oxygen binds t the electronegative properties of the he,me iron changes color.
Globins: family of proteins, hemoglobin belongs to. Myoglobin is a 153 amino acid, made up of eight a-helicalsegments connected in bends.
Hemocytobasts. Precursor stem cells from where hemoglobin arise. Adult hemoglobin contain two types og globin two alpha and two beta.
Two major conformations ofhemoglobin:
R-state: oxygen has a higher affinity for hemoglobin in the R-state.
T-state: when oxygen is absent the t-state is more stable and it predominates in deoxyhemoglobin. The t state is stabilizedby ion pairs.
Hemoglobin has a transition state from low affinity (t-state) to high affinity state (r-state) as more oxygen molecules are bound as a result hemoglobin has a hybrid s-shaped, bindingcurve for oxygen.
Allostering protein: the binding of a ligand to one site affects the binding of properties of another site on the same protein. In hemoglobin if ocygen binds to a heme group, itdoes so first weakly because it binds to a subunit in the T state. Its binding lead, however to conformational changes. Making it easier for oxygen to bind. The last ocygen molecules then binds to aheme group that is already in the R-state.
Allosteric proteins are those having other shapes induced by the binding of ligands referrd to as modulators. The conformational changes induced by thebindings of ligands referred to as modulators.
Modulator a metabolite that when bound to the allosterinc site of an enzyme alters its kinetic characteristics.
Homotropic: when the normal ligand and...