| 1. |
- Håkansson, Anders P, et al.
(författare)
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Enzymatic characterization of dihydrolipoamide dehydrogenase from Streptococcus pneumoniae harboring its own substrate
- 2007
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Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 282:40, s. 30-29521
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Tidskriftsartikel (refereegranskat)abstract
- This study describes the enzymatic characterization of dihydrolipoamide dehydrogenase (DLDH) from Streptococcus pneumoniae and is the first characterization of a DLDH that carries its own substrate (a lipoic acid covalently attached to a lipoyl protein domain) within its own sequence. Full-length recombinant DLDH (rDLDH) was expressed and compared with enzyme expressed in the absence of lipoic acid (rDLDH(-LA)) or with enzyme lacking the first 112 amino acids constituting the lipoyl protein domain (rDLDH(-LIPOYL)). All three proteins contained 1 mol of FAD/mol of protein, had a higher activity for the conversion of NAD(+) to NADH than for the reaction in the reverse direction, and were unable to use NADP(+) and NADPH as substrates. The enzymes had similar substrate specificities, with the K(m) for NAD(+) being approximately 20 times higher than that for dihydrolipoamide. The kinetic pattern suggested a Ping Pong Bi Bi mechanism, which was verified by product inhibition studies. The protein expressed without lipoic acid was indistinguishable from the wild-type protein in all analyses. On the other hand, the protein without a lipoyl protein domain had a 2-3-fold higher turnover number, a lower K(I) for NADH, and a higher K(I) for lipoamide compared with the other two enzymes. The results suggest that the lipoyl protein domain (but not lipoic acid alone) plays a regulatory role in the enzymatic characteristics of pneumococcal DLDH.
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| 2. |
- Ovhed, I, et al.
(författare)
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What is the future of primary care research? Probably fairly bright, if we may believe the historical development
- 2005
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Ingår i: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 23:4, s. 248-253
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To study one aspect of the development of primary care research from 1975 to 2003. Design. Quantitative bibliometric study. Setting. Pub Med database. Subjects. Four Nordic countries (Denmark, Finland, Norway, and Sweden), seven countries from the rest of Europe (Belgium, France, Germany, Italy, the Netherlands, Spain, and the UK), and seven countries from the rest of the world (Australia, Canada, India, Japan, New Zealand, South Africa, and the USA). Main outcome measures. Number of primary healthcare publications per million inhabitants. Percentage of publications in primary healthcare of all publications in human medicine. Results. In 2003, New Zealand, the UK, and Australia were in the lead, with barely 20 primary care publications per million inhabitants, followed by Norway, Sweden, the Netherlands, and Denmark, where the corresponding figure was around 10. A vigorous increase in publications from 1975 to 2003 was clearly seen in most of the countries. However, during the same period the proportion of publications from primary care in relation to all publications in human medicine was only moderately increased, or virtually unchanged. Conclusion. It is believed that primary care research has a future, and it is hoped it may even be bright. However, searching Pub Med gave but one aspect of the historical development, and in particular the comparisons between countries may be questionable.
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