Cheet heet biochem for exam 2

Hb different frm unoxygenated

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: reach 4 in theory. The upper limit in hemoglobin is actually 3. This is normal for allosteric binding. If n is less that 1 there is negative cooperativity. This is very rare. [L] eq Kd → Half of lignad binding sites are occupied[L] < Kd → Less ligand is bound to protein [L] > Kd → More than half of ligand is bound to protein…For example, to have 90% of ligands bound to protein binding sites, [L] has to be 9X greater than Kd. Low Kd → Higher affinity of L to P High Kd → Lower affinity of L to P Competitive Inhibition  ­ As [I] increases, VMAX does not change, yet KM increases Uncompetitive Inhibition – As [I] increases both VMAX and KM decrease. The ratio of the two (specificity constant), however, does not change. Non ­Competitive Inhibition – If Ki,s = Ki,i then we have pure non ­competitive inhibition and if Ki,s ≠ Ki,i then we have mixed (non ­competitive) inhibition. Ribose is a 5 ­carbon sugar, Glucose is a 6 ­carbon sugar, Galactose is an epimer of glucose, Manose is also an epimer of glucose, and fructose is a ketose form of glucose Bohr effect: H+ is is involved in cooperative effects when hemoglobin binds to oxygen.It alters the proteins 3 dimensional structure.Increasing H+ reduces the affinity for oxygenH+ protonates key amino acids and alters the 3 dimensional structure.Metabolizing tissues release H+ and this causes Hemoglobin to release the needed oxygen to the tissues.The oxygenated form of hemoglobin has a lower Pka than the deoxy form.CO2 is also involved in cooperative effects. It forms H2CO3 and acidifies.Hemoglobin can also transport CO2.Oxygen transport in Myoglobin is not effected by H+ or CO2. BPG reduces affinity for oxygen. Binds in cavity between β subunits in T state and stabilizes T state;. Oxygen binding to hemoglobin is regulated by2,3 ­Bisphosph ogl ycerate An Allosteric Effector of Hemoglobin In the absence of 2,3 ­BPG, oxygen binding to Hb follows a rectangular hyperbola! The sigmoid binding curve is only observed in the presence of 2,3 ­BPG Since 2,3 ­BPG binds at a site distant from the Fe where oxygen binds, it is called an allosteric effectorOnly 1 BPG per heme tetramer 5 nanometers = 0.005 micrometers -9 5 nanometers = 5.0 × 10 meters 5 micrometers = 5000 nanometers 1.When asked to determine the Ka after giving a chart of values, find the Vmax and then find ½ Vmax. The subs conc at ½ vmax=Km. 2.when asked to calculate the value of km and vmax using linbuck, take recips of data and then plot on chart. Estimate yint (1/vmax) and xint( ­1/km). 3. When asked to ca...
View Full Document

This note was uploaded on 09/14/2013 for the course CHE 2045 taught by Professor Osegovic during the Fall '12 term at University of South Florida.

Ask a homework question - tutors are online