Spot hemoglobin. Studies on the Root effect hemoglobin of a marine teleost.

摘要: The Spot, Leiostomus xanthrus, has a single tetrameric hemoglobin. Structural studies indicate the presence of alpha- and beta-like chains with COOH-terminal sequences --Arg --TYR-His, respectively, same as is found in human Spot hemoglobin possesses Root effect: heterotropic control mechanism like Bohr effect but more extreme pH dependence equilibria kinetics O2 CO binding. seems to be molecular adaptation, that pH- anion-sensitive hemoglobins may help fish achieve neutral buoyancy by facilitating delivery swim bladder. Changes both "on" "off" processes contribute greatly decreased ligand affinity at low pH. time course ofligand combination biphasic wavelength dependent, suggesting differential on chains. change shape ligand-binding curve interpreted terms proton-dependent transition between (T) high (R) conformations. However, this not only mechanism, since effects two types also observed dependence.