N-terminal amino acid sequences of the alpha and beta chains of the two chicken hemoglobin components

Hemoglobin and myoglobin content in muscles of broiler chickens

The two main heme proteins, hemoglobin and myoglobin, are important factors determining meat quality aspects such as color and hemorrhage. The extent of hemorrhage in muscle tissue can probably be determined by measuring the hemoglobin content. The objective of this study was twofold: 1) to develop a specific and reproducible method to quantify the hemoglobin and myoglobin content in muscle tissue of broiler chickens, and 2) to study the effect of hemorrhage on the hemoglobin content in muscle tissue. We tested several methods to determine the total heme, hemoglobin, and myoglobin content in broiler chicken muscles on their specificity, sensitivity, and reproducibility. Methods based on immunological techniques appeared to be very specific and sensitive. The results obtained applying these methods on muscle tissue extracts were, however, not reproducible due to concentration effects. A combination of spectrophotometric analysis of the total heme protein concentration and measurement of the myoglobin concentration, applying size exclusion chromatography, proved to be a reliable and reproducible method to determine the hemoglobin and myoglobin content in chicken muscles. The total heme, hemoglobin, and myoglobin contents were related to muscle type. Extensive hemorrhage increased the hemoglobin content.

Reduction in potency and reversal of left-shifting activity of BW12C with the major and minor components of chicken hemoglobin

The effects of the left-shifting, anti-sickling compound BW12C (5-(2-formyl-3-hydroxyphenoxy)pentanoic acid) on the oxygen saturation curve of whole chicken blood and the isolated major (AII) and minor (AI) components of chicken hemoglobin have been studied. The results support the postulated major binding mode for BW12C to human hemoglobin of bridging between the alpha-chain terminal amino groups in the oxy conformation with an important hydrophobic component contributed mainly by Pro 77 alpha residues. In chicken AII (Pro 77 alpha----Ser) BW12C still left-shifts at high concentrations but its potency is greatly reduced (at least 10-fold). In chicken AI (Pro 77 alpha----Ser and Val 1 alpha----Met) BW12C is a right-shifter with a potency comparable to that of 2,3-diphosphoglycerate suggesting that binding at the beta-chain termini in the deoxy conformation is now dominant with alpha-chain binding no longer significant.

Nucleotide sequence for a novel duck alpha-globin gene

Nucleotide sequence analysis of a recombinant cDNA for a duck alpha-globin gene indicates a gene with novel features and evolutionary history. The duck alpha-globin double-stranded cDNA, treated with S1 nuclease and tailed with poly(dC), was inserted into the PstI restriction endonuclease site of pBR322 tailed with poly(dG). Nucleotide sequence analysis of the resulting recombinant cDNA indicates that it contains the translated region and all of the 3' untranslated region for an alpha-globin gene. The sequence was determined by procedures designed especially for rapid analysis of pBR322 (PstI site) recombinant cDNAs. This duck globin has sequences related to the chicken alpha-A globin in some regions but in other regions it is more closely related to another alpha globin found in anemic chickens.

Complete nucleotide sequence of a cloned chicken alpha-globin cDNA

Chicken globin double-stranded cDNA was synthesised from anaemic adult reticulocyte alpha- and beta-globin mRNA and ligated into the Hind III site of pBR322 using synthetic Hind III decamers. Transformation of E. coli x1776 resulted in the production of a number of alpha- and beta-cDNA clones. One of the alpha-type clones (pCG alpha-8) was fully sequenced and found to code for neither alpha A- nor alpha D-globin. Partial sequencing of the other alpha-cDNA clones indicates that they are all of the same type.