| 1. |
- Altman, S, et al.
(författare)
-
Catalysis by the RNA subunit of RNase P
- 1989
-
Ingår i: Gene. - : Elsevier BV. - 0378-1119 .- 1879-0038. ; 82:1, s. 63-64
-
Forskningsöversikt (refereegranskat)abstract
- RNase P, an enzyme that contains both RNA and protein components, cleaves tRNA precursors to generate mature 5' termini. The catalytic activity of RNase P resides in the RNA component, with the protein cofactor affecting the rate of the cleavage reaction. The reaction is also influenced by the nature of the tRNA substrate.
|
|
| 2. |
|
|
| 3. |
- Andersson, D.I, et al.
(författare)
-
Antibiotikaresistens här för att stanna?
- 1998
-
Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 95:37, s. 3940-3944
-
Forskningsöversikt (övrigt vetenskapligt/konstnärligt)
|
|
| 4. |
- Andres, J, et al.
(författare)
-
Transition structures for hydride transfer reactions in vacuo and their role in enzyme catalysis
- 1996
-
Ingår i: Journal of Molecular Structure: THEOCHEM. - : Elsevier. - 0166-1280. ; 371, s. 299-312
-
Forskningsöversikt (refereegranskat)abstract
- A general discussion as to the role of in vacuo transition structure in enzyme catalysis is presented. Quantum mechanical aspects are emphasized. The transition structures defined as saddle points of index one (SPi-1) for the hydride transfer step on different model enzyme systems from flavoproteins to dehydrogenases have been characterized with analytical gradients at different levels of theory: semi-empirical; ab initio with different basis sets within the Hartree-Fock scheme; density functional theory using different approaches. Quantum chemical characteristics of the SPi-1 are used to discuss hydride transfer step in enzyme catalyzed reactions and mechanistic implications. With the exception of dihydrofolate reductase, the results for all other systems studied suggest that the endo relative orientation imposed by the active site on the reactants is essential for polarizing the CdHt bond and situating the system in the quadratic region of the endo SPi-1. The geometry and transition vector components are both model independent and weakly dependent on the level of theory used in their determination. Comparisons of the SPi-1 geometries with available X-ray coordinates show that the SPi-1 can be fitted without any stress at the active site. The geometrical arrangement of the SPi-1 results in optimal frontier LUMO orbital interactions, and the transition vector amplitudes show primary and secondary isotope effects to be strongly coupled. A comparison between simple and sophisticated molecular models shows that there is a minimal molecular model associated with geometrical parameters describing the essentials of the chemical interconversion step. For hydride transfer, the corresponding transition vector is an invariant feature.
|
|
| 5. |
- Appelkvist, E L, et al.
(författare)
-
Regulation of coenzyme Q biosynthesis
- 1994
-
Ingår i: Molecular Aspects of Medicine. - 0098-2997 .- 1872-9452. ; 15:Suppl., s. 37-46
-
Forskningsöversikt (refereegranskat)abstract
- The side-chain moiety of coenzyme Q is synthesized by a trans-prenyltransferase present in microsomes. Condensation of this moiety with the precursor ring takes place in the Golgi system. The enzymes involved, as well as the cytosolic geranylgeranyl-PP synthase, are regulated in an independent fashion. When the size of the farnesyl-PP pool is decreased or increased by employing appropriate inhibitors, the rate of CoQ synthesis is modified accordingly, indicating the dependence of trans-prenyltransferase activity on the level of intracellular substrate concentrations. Administration of peroxisome proliferators elevates CoQ concentrations not only in blood, but also in various tissues. Thus, it may be possible in the future to selectively increase CoQ concentrations in certain organs, without increasing the level of cholesterol.
|
|
| 6. |
- Bennich-Björkman, Li, et al.
(författare)
-
A creative university: is it possible?
- 1991
-
Ingår i: Studies of higher education and research, 1991:4. ; 1991:4
-
Forskningsöversikt (refereegranskat)
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Bohlin, Lars, et al.
(författare)
-
Podophyllotoxin derivatives : drug discovery and development
- 1996
-
Ingår i: Drug Discovery Today. - : Elsevier. - 1359-6446 .- 1878-5832. ; 1:8, s. 343-351
-
Forskningsöversikt (refereegranskat)abstract
- The exploration and exploitation of podophyllin formulations provide an example of how a plant extract with established ethnomedical use, but also causing toxicity, can provide a basis for new drug discovery and development. Applications and potential applications include the treatment of venereal warts, psoriasis, rheumatoid arthritis, malaria and Alzheimer's disease. This review addresses the history and pharmacological action of these natural products and outlines the preclinical development and clinical trials of drugs in the pipeline and with marketing approval.
|
|
| 10. |
- Bruhn, Jan G., et al.
(författare)
-
Molecular Pharmacognosy : an explanatory model
- 1997
-
Ingår i: Drug Discovery Today. - : Elsevier. - 1359-6446 .- 1878-5832. ; 2:6, s. 243-246
-
Forskningsöversikt (refereegranskat)abstract
- Increased interest in the study of natural products as potential drugs and rapidly changing research strategies are driving us to reassess the role of pharmacognosy in the wider context of pharmaceutical research. The authors propose a new definition and an explanatory model of modern pharmacognosy that can be used as a theoretical foundation for future development of this classical branch of the life sciences.
|
|
