Akihiko Kajita

Quaternary structure of Limnodrilus haemoglobin.

Structure of the haemoglobin from Limnodrilus gotoi (molecular weight, 3.01 x 10(6)) was studied electron microscopically and chemically. The molecule appears to be a regular hexagonal cylinder having the dimensions 220 A x 160 A, and to consist of 12 identical submultiples arranged six and six into two hexagonal discs laid one above the other. The protein contains 108 haems per molecule and 12 seryl, 12 threonyl, 35 glutamyl and 45 valyl residues to give a total number of 104 residues per molecule as N-terminal amino acids. These results lead us to a conclusion that the minimum molecular weight either per haem or per N-terminal residue is approximately 28,000 and the whole molecule consists of about 108 subunits or peptide chains, each containing single haem. Further it is presumed that submultiple is a nonamer, composed of nine subunits.

Dimeric hemoglobin of the bivalve mollusc Anadara broughtonii: complete amino acid sequence of the globin chain.

The complete amino acid sequence of a dimeric hemoglobin (HbI) from the marine bivalve mollusc Anadara broughtonii was determined by sequencing of the intact chain and peptide fragments produced by cleavage at two asparaginylglycine bonds and at methionyl, arginyl, and tryptophanyl residues. The clam hemoglobin consists of two identical polypeptide chains. The globin chain has 146 amino acid residues with a proline at the NH2 terminus and a leucine at the COOH terminus. The calculated molecular mass of the native hemoglobin was 32945 daltons. The clam hemoglobin contains only two histidine residues, which correspond to the distal and proximal heme-linked positions. Compared with human beta chain, an additional segment of seven residues is present in the NH2-terminal region and also five less residues in the COOH-terminal region. Although such an amino-terminal elongation has been known to be characteristic of hemoglobins from the most primitive living vertebrates Cyclostomata, a very similar structure was found to occur in the hemoglobin from the primitive invertebrate arcid clam.

A simple non-enzymatic method to regenerate oxyhemoglobin from methemoglobin

Abstract Methemoglobin can be reduced to hemoglobin by NADH in the presence of catalytic amount of phenazine-methosulfate. A simple non-enzymatic method to obtain oxyhemoglobin from methohemoglobin was established using NADH-PMS system. Regenerated hemoglobin obtained by this method revealed normal oxygen equilibria in the presence of 2,3-diphosphoglycerate.

The effect of organic phosphates on the allosteric property of Rana catesbeiana hemoglobins

Abstract Difference in the oxygen affinity between tadpole and frog hemoglobins of Rana catesbeiana was investigated in relation to the interaction of organic phosphates with the hemoglobin. The oxygen affinity of both hemoglobins increased remarkably by the stripping procedure. The addition of DPG, ATP and IHP which were proved to be present in the erythrocytes, to the stripped hemoglobins resulted in notable decrease of the oxygen affinity, except that IHP showed little effect on the frog hemoglobin. Affinity constants of organic phosphates for the hemoglobins were obtained from the oxygen equilibrium data. IHP was found to have the highest affinity for tadpole hemoglobin, while DPG was the highest for frog hemoglobin.

Isolation and properties of γ chain from human fetal hemoglobin

Abstract 1. 1. Dissociation of human fetal hemoglobin (FII fraction) into its constituent subunits was investigated electrophoretically. 2. 2. A simple method of isolating the γ chain from fetal hemoglobin is described. The procedure is a slight modification of the method of Bucci and Fronticelli 1 for adult hemoglobin, consisting of p-chloromercuribenzoate treatment at pH 4.7 and fractionation by CM-cellulose column chromatography. 3. 3. One of the three fractions obtained by this method was identified as the γ chain by means of electrophoretic behavior, ultraviolet absorption spectra, alkali resistance and amino-terminal amino acid analysis. The yield of γ chain was 40–60%.

Polymerization of oxygenated and deoxygenated bull-frog hemoglobins

Abstract 1. 1.|The adult bullfrog oxyhemoglobin polymerized to form the 7-S and 11-S molecules when stored in vitro. The reaction was accompanied by the loss of two reactive SH groups per hemoglobin tetramer, and was completely prevented by the treatment of hemoglobin with iodoacetamide. These observations agree essentially with those reported by other authors for the bullfrog hemolysate which was saturated with CO. 2. 2.|The adult bullfrog hemoglobin was found also to polymerize to a 7-S molecule when deoxygenated. The reaction was rapid and reversible with respect to the oxygenation-deoxygenation of the hemoglobin molecule. No reactive SH groups appear to be involved in this polymerization, because iodoacetamide and mercaptoethanol could not prevent the reaction. 3. 3.|The organic phosphates had no effect on the deoxy polymer formation of the stripped bullfrog hemoglobin. 4. 4.|Neither oxy- nor deoxyhemoglobin of the tadpole showed any tendency to polymerize under the same conditions in which the adult hemoglobin polymerized.

Immunological studies in the multiple hemoglobins of tadpole and frog of Rana catesbeiana

It has long been known that the hemoglobins of tadpole and frog of Ranu cufesbeiana occur in multiple forms and the major components of both hemoglobins are remarkably different in function and structure from one another [l-7], whereas little information is available on the properties of their minor components. In an attempt to clarify the immunological properties of multiple hemoglobins in the tadpole and the frog, we have found that all of the hemoglobin components in the frog, as well as in the tadpole, are immunologically indistinguishable from each other. No immunological cross-reactivity was detected between the components of tadpole and frog hemoglobins. Formation of two precipitin bands between the tadpole hemoglobin or globin and rabbit antitadpole hemoglobin serum is also discussed from the point of the dissociation-association equilibrium of the protein.