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A F Riggs

Publications and source records attributed to A F Riggs.

43 records · Page 3Linked to original sources
PubMed1982

The amino acid sequence of a major polypeptide chain of earthworm hemoglobin.

The amino acid sequence has been determined for polypeptide chain AIII of the major component of the hemoglobin (erythrocruorin) from the earthworm, Lumbricus terrestris. The chain has 157 residues and a molecular weight of 17,496. Although the extent of sequence identity with other globin chains is only 17-18%, analysis of the sequence leads to the conclusion that the secondary structure of the chain is very similar to those of vertebrate globins and that about 60-70% of the amino acid residues are in alpha helices. The D helix appears to be missing, as it is from the alpha chain of human hemoglobin and from the monomeric hemoglobin of Glycera dibranchiata, another annelid worm. This is the first sequence obtained from one of the "giant" extracellular hemoglobins of invertebrate animals.

Amino Acid Sequence↗
PubMed1980

Isolation and sequence of the pyridoxal 5'-phosphate active-site peptide from Rhodospirillum rubrum ribulose-1,5-bisphosphate carboxylase/oxygenase.

Ribulose-1,5-bisphosphate carboxylase/oxygenase from Rhodospirillum rubrum was modified with pyridoxal 5'-phosphate and then reduced with sodium borohydride. Both carboxylase and oxygenase activities were lost when one molecule of pyridoxal 5'-phosphate was bound per enzyme dimer. Peptide maps of modified enzyme showed one N6-(phosphopyridoxal)lysine-containing peptide. This peptide was isolated by gel filtration and cation-exchange chromatography and its sequence determined as Ala-Leu-Gly-Arg-Pro-Glu-Val-Asp-(PLP-Lys)-Gly-Thr-Leu-Val-Ile-Lys. Since activation of the enzyme with Mg2+/CO2 enhances pyridoxal 5'-phosphate modification and subsequent inactivation and the substrate ribulose bisphosphate protects against modification, the modified lysyl group is most certainly at the catalytic site and not at the activation site of the enzyme.

Amino Acid Sequence↗
PubMed1966

Lobster hemocyanin: properties of the minimum functional subunit and of aggregates.

Lobster hemocyanin dissociates into a functional subunit of 68,000 to 70,000 molecular weight when Ca(2+) ions are removed from an alkaline solution of low ionic strength. Succinylation results in a further dissociation into two nonfunctional subunits of approximately 34,000 to 35,000 molecular weight. Amino acid analysis and tryptic peptide patterns indicate that the functional subunit is composed of at least two polypeptide chains which are similar.

Animals↗