MBB 222 Lecture Notes - Lecture 12: Allosteric Regulation, Heme, C-Terminus

• School: Simon Fraser University
• Department: Molec Biol & Biochem
• Course: MBB 222
• Professor: Adam Barlev

Document Summary

1 ml of human blood carries ~ 5x109 red blood cells (rbcs) Each rbc contains ~3x108 hemoglobin molecules therefore, blood can carry ~2. 5 mm o2, more than pure water (~1 mm o2) hemoglobin. Hemoglobin (hb) has 4 subunits that are structurally homologous to myoglobin. 2 subunits (141 amino acids each) 2 subunits (146 amino acids each) Each and subunit individually looks like myoglobin, but only 27 amino acids (18%) are conserved (identical) among myoglobin and and subunits of hb. Differences between hb and mb function are all due to the quaternary structure of hb, and these differences are critical for. Hb"s allosteric regulation by co2, h+, and bpg. Heme binds o2 weakly and reversibly, but gases like carbon monoxide (co), hydrogen sulfide (h2s) and ions like cyanide (cn-) very strongly. Co, h2s, cn- are very toxic they bind to hemoglobin and block o2 binding.