lecture_11-Mb_and_Hb

lecture_11-Mb_and_Hb - PROTEIN FUNCTION I Ligand Binding 1...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

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

Unformatted text preview: PROTEIN FUNCTION I Ligand Binding 1 RECAP y = x x + C P + L PL K a = PL [ ] P [ ] L [ ] = fraction of total binding sites occupied = L [ ] L [ ] + 1 K a P + L PL = L [ ] L [ ] + K d 2 3 = O 2 [ ] O 2 [ ] + K d = O 2 [ ] O 2 [ ] + O 2 [ ] 0.5 = pO 2 pO 2 + P 50 O 2 is a gas. More appropriate to express concentrations of gas as pO 2 4 5 EFFECT OF GLOBIN ON O 2 BINDING BY HEME CO binds heme 20,000 times more tightly than O 2 to free heme K d for CO is 20,000 times smaller than K d for O 2 CO binds heme 200 times more tightly than O 2 to heme in myoglobin K d for CO is 200 times smaller than K d for O 2 6 EFFECT OF GLOBIN ON O 2 BINDING BY HEME partially explained by steric hindrance preferred mode of ligand binding by free heme mode of oxygen binding by heme in myoglobin 7 His 64 is referred to as the distal His and does not coordinate to the iron atom, but does interact with the axial ligand (O 2 ) His 93 is the proximal His and does coordinated to the iron but does not interact with O 2 E FFECT OF G LOBIN ON O 2 BINDING BY H EME His 64 His 93 8 His...
View Full Document

Page1 / 7

lecture_11-Mb_and_Hb - PROTEIN FUNCTION I Ligand Binding 1...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online