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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 1 (1967), S. 1-9 
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract By means of horizontal gel electrophoresis and the zymogram technique, genetic variants and the formation of a hybrid molecule of the enzyme alcohol dehydrogenase (ADH) have been found in Zea mays. Each inbred homozygous stock examined showed two types of ADH isozyme patterns: a fast faint zone and a slower deeply staining zone, both anode-migrating at pH 8.5. The variants found differed in that each of the ADH zones varied in its electrophoretic mobility when compared to its counterpart in the other strain. When appropriate genetic crosses were made, the resulting heterozygotes showed the parental ADH zones, and, in addition, a band of intermediate mobility was formed between the deep-staining ADH bands. However, in the fast-moving zone only the parental isozymes were represented in the heterozygote. The formation of the hybrid molecule and the apparent gene dosage effects support the hypothesis that ADH-2 in maize exists as a dimer, whereas ADH-1 may exist as a monomer.
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  • 2
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A single peptide difference has been found in tryptic digests of human transferrins C and DChi. The peptide isolated from Tf C was shown to have the sequence Asp-Ser-Ala-His-Gly-Phe-Leu-Lys. The corresponding peptide from Tf DChi has the composition (Gly, Phe, Leu, Lys). Apparently, histidine of the Tf C peptide has been replaced by lysine or arginine in Tf DChi, producing a new point of attack for trypsin. On the basis of the genetic code, arginine is proposed as the replacement.
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  • 3
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Studies have been conducted on eight sets of monozygous and nine sets of dizygous female Negro twins, both members of whom were heterozygous for G-6-PD deficiency. Twins were studied both by assay of erythrocytic G-6-PD activity and by the methemoglobin elution test (MET). The MET is a procedure which identifies histochemically cells with appreciable G-6-PD activity and permits accurate determination of the percentage of such cells in heterozygotes. Monozygous twins showed significantly less “within-pair” variation than dizygous twins with both the MET and G-6-PD assay. Concerning the significantly greater agreement in MET results in monozygous twins than dizygous twins, our present working hypothesis is that X-chromosomal inactivation in the Negro female is genetically controlled, rather than random. However, certain alternate hypotheses allowing for random X-inactivation have not been excluded; these include somatic cell selection after random X-inactivation, and cell exchange between identical twins in utero/it. Studies in nontwin related heterozygotes now underway should help differentiate among these various possibilities. In addition to the studies on 17 pairs of female twins heterozygous for G-6-PD deficiency, 26 pairs of nondeficient female Negro twins have been studied by G-6-PD assay. Within-pair variation in monozygous twins was significantly less than within-pair variation in dizygous twins in all cases. The genetic influences detected with the G-6-PD assay in the female twins could theoretically be due to nonrandom X-inactivation, to genetically determined quantitative differences in enzyme activity (e.g., isoalleles), or to both. By appropriate calculations, based on the MET results, we have factored out the effects of X-inactivation on overall enzyme activity in the heterozygous deficient twins. After removal of the effect of X-inactivation, monozygous twins heterozygous for enzyme deficiency continue to show significantly less within-pair variation than dizygous twins. This finding indicates significant genetic influences on quantitative G-6-PD activity other than X-inactivation and other than the deficiency allele. This conclusion has been strengthened by studies on male twins where X-inactivation is not present.
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  • 4
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Human glucose 6-phosphate dehydrogenase (d-glucose 6-phosphate: NADP oxidoreductase, EC 1.1.1.49) (A+), an electrophoretically distinguishable variant found in Negroes, was purified by column chromatographic techniques. The sedimentation patterns of analytical ultracentrifugation and interference patterns of sedimentation equilibrium indicate a homogeneous preparation. The molecular weight (by sedimentation equilibrium method) was estimated as 230,000, which was closely similar to that of the normal wild type enzyme (B+). The sedimentation constant of the variant enzyme (S 20,w=9.0) was smaller than that of the B+ enzyme (S 20,w=10.0). The molecular weight was about 45,000 in 4 mguanidine hydrochloride, indicating that the A+ enzyme, as well as the B+ enzyme, consisted of six subunits of similar size. The optimal pH of the variant enzyme was slightly higher than that of the B+ enzyme. In contrast to the B+ enzyme, magnesium ion increased the A+ enzyme activity with NAD as substrate. The Michaelis constants and the turnover rate were similar to those of the B+ enzyme. The A+ enzyme was serologically indistinguishable from the B+ enzyme when the anti-B+ serum was used as antibody. No significant difference was found in the amino acid composition of acid hydrolysates of the B+ and the A+ enzymes. This does not exclude an amino acid substitution, and, in fact, a single amino acid substitution, i.e., asparagine in B+ and aspartic acid in A+ enzyme, has been found and is being being reported separately.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 1 (1967), S. 197-203 
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
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  • 6
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A variant of glucose 6-phosphate dehydrogenase (G6PD) in Drosophila melanogaster shows different electrophoretic migration in males and females. In heterozygotes, the variant influences the migration of G6PD produced by both chromosomes. Mixing of homogenates of males and females changes migration of the female-produced enzyme, suggesting that a protein produced in males is capable of altering the variant G6PD molecule. The hypothetical protein is also present in pseudomales and intersexes produced by sex transformation genes.
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  • 7
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Following injection of newly formed female pupae or adult Drosophila with C 14 -labeled β-alanine, appreciable labeled free β-alanine was retained in the internal organs for at least 24 hr. Ebony retained most, while heterozygotes were intermediate. Part of the β-alanine-2-C-labeled portion of the molecule was bound to the internal organs, especially the ovaries and mature egg follicles. Dissected normal pupal cuticles incorporate β-alanine-1-C as directly related to the degree of tanning. KCN, ethanol, or air exclusion inhibit incorporation. Tan pigment and radioactivity are extractable from the cuticles by hydrazine-ethanol. A β-alanine precursor is uracil. Injected β-alanine immobilizes ebony, but not normal, flies (newly emerged) and inhibits glucose, but not glucose 6-phosphate metabolism. Desiccated ebony adults take up water more readily than normal adults.
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  • 8
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Somatic hybrids of drug-resistant mutant hamster and mouse cell lines have been isolated and propagated in long-term culture and have been studied in respect to karyotype and three enzymes. During the course of propagation the long-surviving hybrid clones show progressive loss of telocentric chromosomes associated in at least one case with loss of mouse enzyme. Hybrid clones showed hybrid molecules for malate dehydrogenase (MDH), lactate dehydrogenase (LDH), and 6-phosphogluconate dehydrogenase (6PGD) made up by recombination of parental subunits.
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  • 9
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract At the gene locus for liver alcohol dehydrogenase (ADH) of the Japanese quail, three alleles which give electrophoretic variants, A, B, and C, exist. This enzyme is autosomally inherited. Allelic polymorphism was not observed in the chicken, but the wild-type ADH of the chicken can readily be distinguished from A, B, and C of the quail by starch gel electrophoresis. In the development of both species, ADH activity reached a near adult level at about the nineteenth day (a few days after hatching in the quail and a few days before hatching in the chicken). Chicken-quail hybrids at the day of hatching (nineteenth day) revealed the presence of maternally derived quail ADH only, and their ADH activities were about half that of both parental species. Those hybrids which received either A or C allele from the mother quail showed three bands of ADH at the third day after hatching. The chicken and quail alleles began to function in synchronous harmony. One 3-day-old and two adult hybrids which received B allele from the quail, however, still revealed complete absence of the paternally derived chicken ADH.
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  • 10
    ISSN: 1573-4927
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract This paper describes the physicochemical characteristics in partially purified enzyme on subjects with the Pd A, Pd AB, and Pd B variants of 6-phosphogluconic dehydrogenase (6PGD). For these studies, whole blood was purified about 225-fold using ion exchange chromatography on DEAE cellulose column and fractionation with ammonium sulfate. 6PGD emerges as a single peak between 0.01 m and 0.1 m phosphate buffer on the column and is precipitated in the 55–80% fraction of ammonium sulfate. This purified enzyme can be stored frozen for several months without appreciable loss of activity and contains no detectable activity of glucose 6-phosphate dehydrogenase and glutathione reductase. The three variants of partially purified 6PGD varied from each other in two respects. The transitional temperature is 47.8 C for Pd A, 45.4 C for Pd AB, and 41.1 C for Pd B. The K m for 6PGA is 30 μm for Pd A, 21 μm for Pd AB, and 15 μmfor Pd B. These observations add further strength to the concept that the polymorphism in 6PGD represents alterations in either the configuration or structure of the protein molecule itself.
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