Structural and Functional Characterization of the Hemoglobin from Lumbricus terrestris
The extracellular Hb of the earthworm Lumbricus terrestris has an M m near 3,800 kDa (1) and is composed of four major kinds of 02-binding chains: a, b and c which form a disulfide-linked trimer, and chain d which is not covalently linked to any other chain (2, 3). Amino acid sequencing has shown both the position of the intra-molecular disulfide bond in each of the four chains and the positions of interchain disulfide bonds in the trimer (4, 5). Analyses of the heme content of the intact Hb, the abc trimer, and of isolated subunits a, b, c and d indicate that the intact molecule has 2200 g of non-heme protein per mole of heme (6). This value corresponds to 35,200 g of non-heme protein per one twelfth subunit, a value which appears to be consistent with those for bands V and VI observed with SDS-PAGE (7). An emerging picture of the structure of the intact molecule is that it consists of 192 heme-containing chains and 12 nonheme chains, at least some of which are required for the assembly of the intact molecule (8).
KeywordsGuanidine Hydrochloride Sodium Dithionite Intact Molecule Bohr Effect Cellulose Chromatography
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- 1.Vinogradov, S.N. (1985) Comp. Biochem. Physiol. B 82: 1–15.Google Scholar
- 2.Fushitani, K., Imai, K. and Riggs, A.F. (1980) In Invertebrate Oxygen Carriers, ed. B. Linzen, 77–79. Berlin: Springer-Verlag.Google Scholar
- 11.Walz, D.A., Snow, J., Mainwaring, M.G. and Vinogradov, S.N. (1987) Fed. Pro. 46: 2266.Google Scholar