PHGY 313 Lecture Notes - Lecture 6: Cytoglobin, Oncotic Pressure, Heme
24 May 2016
School
Department
Course
Professor
Document Summary
Main role in vertebrates is to transport o2 (250ml of o2/min) Other globins: muscle myoglobin (mb), nerve cell neuroglobin (ngb), and cytoglobin (cgb) In vertebrates, hb is paced into rbc rather than dissolved in plasma: inclusion of hb in rbc reduces oncotic pressure and high blood viscosity, hb is freely dissolved in body fluids of many invertebrates. Composed of 2 alpha and 2 beta chains, forming 2 alpha-beta pairs. Each subunit contains one o2 binding heme group; each hb binds 4 o2: heme consists of 4 pyrol, which absorbs light and gives heme its red colour, each heme contains an iron center (fe2+) Gene structure and globin folding is very conserved among mammals though. O2 binding to iron is stabilized by the distal histidine residue. O2 affinity of hb in the oxygenated r state is higher than that of hb in the deoxygenated t state.
