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- Cederlund, Ella, et al.
(författare)
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Characterization of new medium-chain alcohol dehydrogenases adds resolution to duplications of the class I/III and the sub-class I genes
- 2011
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Ingår i: Chemico-Biological Interactions. - : Elsevier Science B.V., Amsterdam.. - 0009-2797 .- 1872-7786. ; 191:03-jan
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Tidskriftsartikel (refereegranskat)abstract
- Four additional variants of alcohol and aldehyde dehydrogenases have been purified and functionally characterized, and their primary structures have been determined. The results allow conclusions about the structural and evolutionary relationships within the large family of MDR alcohol dehydrogenases from characterizations of the pigeon (Columba livia) and dogfish (Scyliorhinus canicula) major liver alcohol dehydrogenases. The pigeon enzyme turns out to be of class I type and the dogfish enzyme of class III type. This result gives a third type of evidence, based on purifications and enzyme characterization in lower vertebrates, that the classical liver alcohol dehydrogenase originated by a gene duplication early in the evolution of vertebrates. It is discernable as the major liver form at about the level in-between cartilaginous and osseous fish. The results also show early divergence within the avian orders. Structures were determined by Edman degradations, making it appropriate to acknowledge the methodological contributions of Pehr Edman during the 65 years since his thesis at Karolinska Institutet, where also the present analyses were performed.
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| 3. |
- Norin, Annika
(författare)
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Medium chain dehydrogenases/reductases : alcohol dehydrogenases of novel types
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The medium chain dehydrogenase/reductase (MDR) superfamily is separated into at least eight families, of which the dimeric alcohol dehydrogenase (ADH) is one. Including species variants, close to 1000 MDR forms have been characterized. The dimeric ADHs are Zn-metalloenzymes that catalyze the reversible oxidation of alcohol to aldehyde/ketone using NAD+/NADH as electron acceptor/donor. ADHs are involved in many important functions, such as protection against a variety of toxic compounds, regulation of hormone and growth factor effects, and participation in the intermediary metabolism. Differences in isozyme distribution among populations have been correlated with diseases. The non-MDR aldehyde dehydrogenase (ALDH) family is more diverse than the ADHs, consisting of 17 known functional genes in the human. ALDH catalyzes the oxidation of aldehydes to carboxylic acids using NAD(P)+/NAD(P)H as electron acceptor/donor. This thesis concerns structural, functional and evolutionary relationships of the MDR enzymes. Comparisons with the ALDH family have also been included regarding certain patterns recognized through the extensive studies of ADH. ADH3 is of ancient origin, slowly evolving, has a well-defined function and has two segments of variability located in nonfunctional areas. A conserved pattern has now been shown to occur also in the constant ALDH2 and ALDH9 forms. Thus, although ADH and ALDH are of completely different origins, they appear to have certain similarities in overall evolutionary pathways. A new form of formaldehyde dehydrogenase, from the Gram-positive bacterium Amycolatopsis methanolica, was shown to be a distant member of the MDR superfamily. This enzyme (MD-FDH) utilizes mycothiol instead of glutathione when forming the actual substrate, the thiohemiacetal with formaldehyde. The primary structure determined was aligned and modeled into the human ADH1beta crystal structure. By docking the mycothiolformaldehyde adduct into the active site pocket of the model, it was found that three polar residues are able to provide the interactions necessary for binding. MD-FDH was found to have an evolutionary position intermediate between those of the dimeric ADHs and other families of the MDR superfamily. Nicotinoprotein (Np-ADH) from A. methanolica was also characterized. It has a tightly bound redoxactive cofactor (NAD+). The reducing equivalents do not physically exchange with those of the cytosolic NAD(P)-pool. They are either transferred to the respiratory chain, temporarily stored and subsequently returned to the substrate, or donated to a second substrate. The Np-ADH primary structure determined was modeled into the crystal structure of human ADH1beta, allowing establishment of the overall relationship to the MDR superfamily and identification of additional interactions with the cofactor, compatible with the nicotinoprotein properties of Np-ADH. We also characterized mushroom ADH3 from Agaricus bisporus and yeast ADH3 from Saccharomyces cerevisiae. The studies showed a strong evolutionary restriction on the catalytic properties and emphasized the central role of ADH3 as an enzyme in formaldehyde detoxification.
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- Svenberg, Linus, et al.
(författare)
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Investigation of the Chemical Inhibition Effect of Ground Elder (Aegopodium podagraria) on Timothy (Phleum pratense)?Introducing High School Students to Analytical Chemistry and Chemical Ecology
- 2023
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Ingår i: Journal of Chemical Education. - : American Chemical Society (ACS). - 0021-9584 .- 1938-1328. ; 100:3, s. 1227-1236
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Tidskriftsartikel (refereegranskat)abstract
- The understanding of analytical chemistry and its application in different areas of life science is something that should be encouraged for students studying chemistry, and also something that appeals to many students. Life science includes a vast variety of areas, out of which some are more easily approached in student projects. The chemical communication between organisms, such as plants, as described in chemical ecology is one example. It is therefore beneficial to offer students inquiry-based project work that allows them to explore, and gain a deeper understanding of, this discipline within the grand context that is chemistry. Hence, the present work describes the application of analytical chemistry using gas chromatography-mass spectrometry, including sample preparation for the study of chemical inhibitory (allelopathic) properties of compounds found in the plant Aegopodium podagraria. The questions posed to the students performing this project work were "What compounds can be found in the extracts of the plant?", "Are the extracts allelopathic?", and "Can you determine which compounds contribute to the possible allelopathic properties?". The reported results indicate that the extracts might have allelopathic properties and showed that the extracts contained compounds such as alpha-pinene and beta-caryophyllene. The identified terpenes were shown to have minor allelopathic properties by themselves but displayed an impact on the germination of seeds and length of the sprouts when applied as a blend. This project, and its results, proposes a framework for investigation of other plants and can be adapted to suit students at different academic levels.
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