Tryptic peptides from the beta polypeptide chain of AII component of chicken hemoglobin.

The aminoethylated beta polypeptide chain in AII component from the hemoglobin of adult chicken was digested with trypsin [EC 3.4.21.4] and the resulting peptides were separated and purified by ion exchange chromatography, paper chromatography, and gel filtration. Eighteen tryptic peptides, which were nonoverlapping, accounted for all of the amino acid residues in the beta polypeptide chain. The amino acid sequences of the tryptic peptides were established by a combination of enzymatic digestion and subtractive Edman degradation.     

On the tryptic peptides from hemoglobin chains of six carnivores

Summary The amino acid compositions of the tryptic peptides of the following carnivore hemoglobin chains have been determined: gray fox (Urocyon cineroargenteus); raccoon (Procyon lotor); polar bear (Thalarctos maritimus); coati mundi (Nasua nasua) chain; coati mundi (Nasua narica) two chains; cat (Felis catus) chain; and lion (Panthera leo) chain. These provide a basis for future sequencing of these hemoglobins and construction of an evolutionary tree. The specific results are summarized in the following article (Stenzel and Brimhall, 1977).     

Isoelectric focusing of tryptic peptides from hemoglobin subunits by immobilized pH gradients

The technique of isoelectric focusing on immobilized pH gradients (IPG) has been applied to the analysis of tryptic digests of alpha- and beta-chains of human hemoglobin. Using peptides purified by RP-HPLC as a reference, it was possible to create a peptide map in the single IEF dimension. Unfortunately, it was not possible to find experimental conditions (medium for migration and staining) which would allow the detection of peptides of less than 10-12 residues. Almost all the bands visible on the gel could be assigned to known peptides. In order to obtain these results the IPG runs were performed in 8 M urea containing 0.5% carrier ampholytes and the gel stained with colloidal Coomassie brilliant blue G-250, in the presence of a high-salt concentration and at acidic pH.     

Dinitrophenylated thiols in tryptic fragments of the heavy chain from chicken gizzard myosin

Trypsin digestion of phosphorylated and 3H-labeled dinitrophenylated chicken gizzard myosin released major fragments of Mr 29,000, 50,000 and 66,000 in a ratio of close to one to one. They contained 58% of the label bound to thiols of the heavy chains; 28% of the label was bound to the light chains. The heavy chain fragments of Mr 29,000 and Mr 66,000 were dinitrophenylated when the enzyme activity was inhibited. The 3H-labeled dinitrophenylated myosin alone followed a somewhat different pattern in that the label was bound to the light chains predominantly. Thiolysis of the phosphorylated and dinitrophenylated myosin with 2-mercaptoethanol restored the K+ -ATPase (ATP phosphohydrolase, EC 3.6.1.32) activity and the dinitrophenyl group was removed from the N-terminal fragment of Mr 29,000 of the heavy chain, predominantly. In contrast, restoration of the enzymic activity occurred in thiolyzed dinitrophenylated myosin alone when the label was removed from the light chains rather than the tryptic fragments of the heavy chain. Phosphorylation induced conformational changes in gizzard myosin that altered the reactivity of the thiols in fragments of the globular heavy chain region.     

The tryptic peptides of coyote (Canis latrans) hemoglobin

The tryptic peptides from α- and β-chains of coyote (Canis latrans) hemoglobin have been isolated and their amino acid compositions determined. The compositions are identical to those previously found for dog hemoglobin in all respects except one: the αT-13 peptide of coyote has only threonine at residue 130 of the chain. This indicates only one α-chain in coyote instead of two as in dog, which has one α-chain with threonine and one α-chain with alanine at this position. The α-chain from wolf (Canis lupus) is like that from coyote in having only threonine at residue 130.     

Secondary ion mass spectra of tryptic peptides of human hemoglobin chains

Secondary ion mass spectra of tryptic peptides of human globin alpha-, beta-, gamma and delta-chains were studied. Almost all mass peaks of protonated molecular ions of tryptic peptides were observed and they were very stable and abundant. The present results show the possibilities for quantitative analysis of two gamma-globin species: A gamma and G gamma chains, and for structural analysis of unknown abnormal hemoglobins.     

The structural and functional analysis of the hemoglobin D component from chicken

Oxygen binding by chicken blood shows enhanced cooperativity at high levels of oxygen saturation. This implies that deoxy hemoglobin tetramers self-associate. The crystal structure of an R-state form of chicken hemoglobin D has been solved to 2.3-A resolution using molecular replacement phases derived from human oxyhemoglobin. The model consists of an alpha2 beta2 tetramer in the asymmetric unit and has been refined to a R-factor of 0.222 (R-free = 0.257) for 29,702 reflections between 10.0- and 2.3-A resolution. Chicken Hb D differs most from human oxyhemoglobin in the AB and GH corners of the alpha subunits and the EF corner of the beta subunits. Reanalysis of published oxygen binding data for chicken Hbs shows that both chicken Hb A and Hb D possess enhanced cooperativity in vitro when inositol hexaphosphate is present. The electrostatic surface potential for a calculated model of chicken deoxy-Hb D tetramers shows a pronounced hydrophobic patch that involves parts of the D and E helices of the beta subunits. This hydrophobic patch is a promising candidate for a tetramer-tetramer interface that could regulate oxygen binding via the distal histidine.     

A comparison of the tryptic peptides of hemoglobin from two microtine genera: Clethrionomys and Ondatra

The composition of tryptic peptides was determined for Hb (major or fast electrophoretic component) from Clethrionomys rutilus and from Ondatra zibethicus. Analysis of the separated and β-Hb chains made possible the definition of theT9 and βT12 peptides and the resolution of uncertainties in earlier Microtus data for peptides T9,T12b,βT9,βT12 and βT13. The previous postulate of two deletions in peptide βT5 is supported by the present data, and the independent dipeptide βT6 appears in the Ondatra Hb. A Microtus stem sequence is inferred and used for comparison with the new data, and cladograms are given to accomodate the extended phylogenetic progression.     

Characterization of tryptic peptides from porcine haptoglobin light chain and an amino acid sequence.

The tryptic peptides derived from porcine haptoglobin light chains have been separated and characterized by composition, chromatography, electrophoretic mobility, and partial sequencing. Depending on homology with the corresponding human polypeptide, the amino acid sequence of the chain is proposed. Twenty differences from the human chain are indicated in the total of 84 residues.