The homozygous state for Hb Crete [beta129 (H7) Ala-->Pro] is associated with a complex phenotype including erythrocytosis and functional anemia.

Hb Crete, an electrophoretically neutral, unstable, high oxygen affinity variant, was characterized by protein and DNA analyses in the homozygous state in a 32-year-old woman from Crete, with erythrocytosis and microcytosis. The proband and members of her family over 3 generations, including 5 carriers of Hb Crete, were subject to clinical, hematological and biochemical investigations, and DNA, RNA and protein studies were carried out. The proband demonstrated features associated with disturbed hemoglobin (Hb) structure and function, including erythrocytosis and additionally a state of functional anemia, the latter reflected by increased erythropoetin levels and cardiac output.

Short insertion in a hemoglobin chain: Hb Esch, an unstable alpha1 variant with duplication of the sequence Ala65-Leu-Thr-Asn68.

Hemoglobin (Hb) Esch, is an alpha1 variant, expressed at less than 5%, resulting from the duplication of the 12 nucleotides corresponding to CD65 through 68. The effect of this insertion is the repetition of the sequence Ala-Leu-Thr-Asn, which corresponds to the last turn of helix E. In this variant the presence of a one-turn elongated helix E causes instability and increased ligand affinity.

Hb O-Tibesti [beta121(GH4)Glu-->Lys; beta11(A8)Val-->Ile], a hemoglobin variant carrying in the same beta chain the substitutions of Hb O-Arab and Hb Hamilton, found in combination with Hb S [beta6(A3)Glu-->Val].

Hb O-Tibesti, carries in the same chain the substitution of Hb O-Arab [beta121(GH4)Glu-->Lys] and that of Hb Hamilton [beta11(A8)Val-->Ile]. Hb O-Tibesti may be distinguished from Hb O-Arab by polyacrylamide gel electrophoresis in the presence of urea and Triton-X100, and by reversed phase high performance liquid chromatography. It was found in a compound heterozygous condition with Hb S [beta6(A3)Glu-->Val] in a child of Chad-Sudanese descent, suffering from a sickle cell syndrome.

New alpha 2 globin chain variant with low oxygen affinity affecting the N-terminal residue and leading to N-acetylation [Hb Lyon-Bron alpha 1(NA1)Val --> Ac-Ala].

Hemoglobin Lyon-Bron was found in two members of a family of German ascent presenting with a moderate normocytic anemia. In this alpha 2 globin variant, the N-terminal valine of the chain was replaced by an alanine. Electrospray mass spectrometry of the alpha chain showed that, as normally, the initiator methionine was cleaved during globin processing but that the N alpha-terminal group was totally acetylated.

Hemoglobin Porto Alegre forms a tetramer of tetramers superstructure.

The effects of the mutation beta9(A6)Ser --> Cys on the interactions between the human hemoglobin molecules were investigated, and comparisons were made with other variants having an additional cysteine residue. In hemoglobin Porto Alegre (PA), the beta9 mutation induces polymerization by forming interchain disulfide bonds via the extra cysteine. The hemolysate from a heterozygote was separated by gel filtration into a tetrameric fraction and a higher-molecular-weight oligomeric fraction (30%).

Abnormal hemoglobins: laboratory methods.

Laboratory methods allowing the detection and characterization of hemoglobin variants are reviewed. Protein chemistry techniques such as isoelectrofocusing, electrophoreses under various experimental conditions, cation exchange and reversed phase high performance liquid chromatography, are the most frequently used for the detection of variants. When associated with a few additional data they may lead to a presumptive diagnosis.

Hb Mont Saint Aignan [beta128(H6)Ala-->Pro]: a new unstable variant leading to chronic microcytic anemia.

Hb Mont Saint-Aignan [beta128(H6)Ala-->Pro] is a mildly unstable variant, associated with hemolytic anemia, marked microcytosis and increased alpha/beta biosynthetic ratio (1.55 versus 1.1 +/- 0.

Hb Sitia [beta128(H6)Ala-->Val]: an unstable variant with a substitution in the alpha1beta1 interface.

Hb Sitia [beta128(H6)Ala-->Val] was found in a Greek female with slightly reduced red blood cell indices. The abnormal hemoglobin was indistinguishable from Hb A by electrophoresis but eluted after Hb A on cation exchange high performance liquid chromatography. DNA sequence analysis revealed a GCT-->GTT mutation at codon 128, which is predicted to encode an Ala-->Val substitution.

Hb Ernz [beta123(H1)Thr-->Asn] and Hb Renert [beta133(H11)Val-->Ala]: two new neutral variants revealed by reversed phase high performance liquid chromatography analysis.

Analysis of globin chains by reversed phase high performance liquid chromatography, used as an additional tool for characterizing hemoglobin variants, has led to the discovery of a new class of variants that display only differences in hydrophobicity. Two such variants are here described. Hb Ernz was found in a man of Italian origin who was polycythemic, and in two of his three daughters who were hematologically normal.

Isolation of oligopeptides from the water-soluble extract of goat cheese and their identification by mass spectrometry.

A procedure for the separation and identification of small peptides from the water-soluble fraction of a goat cheese was developed. The water-soluble extract was ultrafiltered (1000 Da membrane cutoff), and peptides were isolated by sequential chromatography: size exclusion chromatography (HPLC-grade water), anion exchange chromatography (phosphate buffer gradient), and semipreparative reverse-phase high-performance liquid chromatography (water/acetonitrile gradient). The fractions obtained were analyzed by combined mass spectrometry methods including electrospray ionization, liquid secondary ionization, and tandem mass spectrometry to identify and to confirm the sequences of 28 tri- to octapeptides naturally appearing in goat cheese during ripening.

Two new variants with the same substitution at position beta122: Hb Bushey [beta122(GH5)Phe-->Leu] and Hb Casablanca [beta65(E9)lys-->Met; beta122(GH5)Phe-->Leu].

Hb Bushey, found in a Chinese baby and his father, is a new variant with a point mutation leading to the substitution Phe-->Leu at position beta122. Hb Casablanca, found in a family from Morocco, is a further example of a hemoglobin variant that carries two abnormalities in the same chain; the first is identical to that of Hb Bushey and the second to that of Hb J-Antakya [beta65 (E9)Lys-->Met]. Structural abnormalities of both Hbs were determined by protein chemistry methods including electrospray and tandem mass spectrometry.

Differentiation of O-acetyl and O-carbamoyl esters of N-acetyl-glucosamine by decomposition of their oxonium ions. Application to the structure of the nonreducing terminal residue of Nod factors.

Nod factors are substituted N-acyl chito-oligomers secreted by plant symbiotic bacteria of the Rhizobium family. Substitutions on the oligosaccharide core specify their recognition by host plants. A method using tandem mass spectrometry is proposed to locate the O-acetyl and O-carbamoyl substituents on the nonreducing terminal residue of the chito-oligomers.

Two new Ggamma chain variants: Hb F-clamart [gamma17(A14)Lys-->Asn] and Hb F-Ouled Rabah [gamma19(B1)Asn-->Lys].

Two new fetal hemoglobin variants affecting the Ggamma chain are reported. Hb F-Clamart was found during investigation of a French newborn who presented with a mild microcytemia. The second variant was found during neonatal screening for hemoglobinopathies of 30,000 babies from a population-at-risk living in the Paris region.