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| 12. |
- HJELMQVIST, L, et al.
(author)
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The vertebrate alcohol dehydrogenase system: variable class II type form elucidates separate stages of enzymogenesis
- 1995
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 92:24, s. 10904-10908
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Journal article (peer-reviewed)abstract
- A mixed-class alcohol dehydrogenase has been characterized from avian liver. Its functional properties resemble the classical class I type enzyme in livers of humans and animals by exhibiting low Km and kcat values with alcohols (Km = 0.7 mM with ethanol) and low Ki values with 4-methylpyrazole (4 microM). These values are markedly different from corresponding parameters of class II and III enzymes. In contrast, the primary structure of this avian liver alcohol dehydrogenase reveals an overall relationship closer to class II and to some extent class III (69 and 65% residue identities, respectively) than to class I or the other classes of the human alcohol dehydrogenases (52-61%), the presence of an insertion (four positions in a segment close to position 120) as in class II but in no other class of the human enzymes, and the presence of several active site residues considered typical of the class II enzyme. Hence, the avian enzyme has mixed-class properties, being functionally similar to class I, yet structurally similar to class II, with which it also clusters in phylogenetic trees of characterized vertebrate alcohol dehydrogenases. Comparisons reveal that the class II enzyme is approximately 25% more variable than the "variable" class I enzyme, which itself is more variable than the "constant" class III enzyme. The overall extreme, and the unusual chromatographic behavior may explain why the class II enzyme has previously not been found outside mammals. The properties define a consistent pattern with apparently repeated generation of novel enzyme activities after separate gene duplications.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Jörnvall, H, et al.
(author)
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The alcohol dehydrogenase system
- 1995
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In: Advances in experimental medicine and biology. - Boston, MA : Springer US. - 0065-2598. ; 372, s. 281-94
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Journal article (peer-reviewed)
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| 17. |
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| 18. |
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| 19. |
- Michaëlsson, Gerd, et al.
(author)
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Increased lymphocyte infiltration in duodenal mucosa from patients with psoriasis and serum IgA antibodies to gliadin
- 1995
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In: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 133:6, s. 896-904
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Journal article (peer-reviewed)abstract
- In a screening study concerning IgA and IgG antibodies to gliadin (IgA AGA and IgG AGA, respectively) in psoriasis, raised levels of IgA and AGA were found to be more common than in a reference group. To determine whether elevated AGA levels were associated with an increased number of intraepithelial lymphocytes, 33 patients with IgA AGA (n = 28) or IgG AGA (n = 5) values above 90% of the reference values (> 50 units/ml IgA AGA and < 12 units/ml IgG AGA) underwent gastroduodenoscopy and duodenal biopsy in a prospective study. For comparison, six patients with low levels of both IgA AGA and IgG AGA were included. Five biopsy specimens were taken in each patient. Paraffin-embedded specimens were examined with regard to the degree of intraepithelial lymphocyte infiltration, and scored from 0 to 3. Biopsy specimens with a score of 0 had one mononuclear cell or less per four epithelial cells. The specimens were also examined with regard to the presence of intraepithelial CD3+ T lymphocytes and gamma/delta+ T lymphocytes. In the six patients with low IgA AGA and low IgG AGA, the biopsy score was 0. Fourteen of the 33 patients with raised AGA had a score of > or = 1; of these, 12 had raised IgA AGA and two had slightly raised IgG AGA. Two of the patients with raised IgA AGA had partial villous atrophy, but the majority had normal villous architecture. There was a significant correlation both between the biopsy score and the number of intraepithelial CD3+ cells and between the score and the number of intraepithelial gamma/delta+ positive T lymphocytes. The serum IgA AGA levels were significantly correlated with the duodenal biopsy score, the number of intraepithelial gamma/delta+ T lymphocytes, and the number of CD3+ intraepithelial T lymphocytes. Most patients had no, or only mild, gastrointestinal symptoms. Of the 14 patients with biopsy scores > or = 1, seven had severe psoriasis and five moderately severe psoriasis, whereas only two had mild psoriasis. There was no relationship between the duodenal score and haemoglobin, folate, whole blood selenium or serum zinc levels. Some of these patients improve on a gluten-free diet, but it is still too early to draw any definite conclusions concerning the type of relationship between the skin lesions, the increased number of intraepithelial lymphocytes in the duodenal mucosa and gluten hypersensitivity.
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| 20. |
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