Reversible protein phosphorylation plays a pivotal role in cellular signal transduction, moderating such diverse functions as neurotransmission, muscle contraction, glycogen synthesis, T-cell activation and cell proliferation.1-5 Serin/threonine phosphatases, which are responsible for protein dephosphorylation. Of the serine/threonine phosphatases, protein phosphatases 1 and 2A (PP1 and PP2A, respectively) share sequence identity between both enzyme subunits (50% for residues 23-292; 43% overall), are present in all eukarytoic cells and are together responsible for 90% of all cellular dephosphorylation. An interesting link between PP1 and PP2A is their shared sensitivity towards a structurally diverse family of natural products: the okadaic acid (1) class of compounds.

Introduction of a fluorescence chromaphore into bifunctional crosslinkers is designed to assign two different functions. Normal crosslinker properties together with a fluorescence signal for quantification. As an example of this type of fluorescent-labeled crosslinker, dansyl-labeled heterobifunctional crosslinker with an NHS ester and sulfhydryl group was synthesized. The application of the synthesized crosslinker was demonstrated by conjugation of bovine serum albumin (BSA) to the surface of maleimide-containing liposome.

A structurally novel, 2,3 seco analogue of fentanyl has been synthesized by a short and efficient procedure. Central-analgesic activity was found to be ca. 30 times lower than fentanyl but still several times higher than morphine.

A mechanism based, photoaffinity labelled inhibitor of the enzym tocopherol cyclase was synthesized

Nature is a rich source of products with interesting and useful biological activity. In the field of crop protection natural products and analogues have successfully been introduced to the market to control insect pests, plant diseases and weeds. The search for new natural products with promising activity continues in academia and in industry, to initiate and to foster novel, ecologically and economically sound crop protection solutions.

The selective epimerisation of the cyclic depsiheptapeptide (cyclopeptolide HUN-7293) 1 at a single amino acid (Leu5) was achieved in four steps. A regio-selective thionation at one of its six amide-bonds provided the corresponding thioamide 2, which upon S-benzylation followed by an unusual silver-promoted intra-molecular cyclisation, was converted to the 2- aminooxazole derivative 4. Re-opening of the oxazole ring by acid hydrolysis regenerated the cyclopeptolide, but preferentially with inverted stereochemistry at Leu5 5. The influence of this inversion on the backbone conformation is discussed

More explicit catalogs should be required from chemical companies. Chemists may have to search references in many databases before to decide to buy a product. For each solid state crystallized phase, the corresponding CSD, ICSD or PDB entry number should be given in catalogs, in addition to the generally provided CAS number. This would be a kind of proof that the compound has been somewhere submitted to the highest characterization level: a crystal structure determination. This would save considerable time and improve confidence in the sample quality. Powder diffraction has a key role to play in this process, if ever realized.

The article recommends JCAMP-DX format for spectroscopic data publication, if the standard for a particular type of spectrum is defined in JCAMP-DX protocol. For those spectra the formats are not available from JCAMP-DX, Galactic

Todays pharmacology supposes that pharmaceutical agents interact with various physiological receptors which are the targets for neurotransmitters, hormones and other endogenous bioregulators [1]. The same physiological effects can be induced by activation/inhibition of different receptors. Contrary, interaction with several receptors can decrease the effects, induced by each receptor separately. Therefore, the prediction of probable receptor targets for substance is important for design of agent with desirable pharmacological effect.

Computer prediction of biological activity spectra for drug-like organic substances is presented. New leads found on the basis of predicted biological activity spectra are considered. Possibilities for in house and Internet applications of this approach in computer-aided drug discovery are discussed.