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The binding sites of a maltose-binding protein (MBP) can be anticipated by a 'binary docking' method involving two MBP octapeptide sequences with mutations that prevent maltose chemotaxis. The peptides in the docked solution permit the construction of an MBP-receptor complex. The dependability of this technique gives it great promise in foreseeing protein-protein and peptide-protein interactions, a necessary step in drug design.

The synthesis and design of a series of novel spiro scaffolds inspired by the novel spiro structures of a number of bioactive natural products such as the histrionicotoxins is reported. An unusual rearrangement of a 1-acyl-1,9-diazaspiro[5,5]undecane to the corresponding 9-acyl-1,9-diazaspiro[5,5]undecane is also reported.

The relationship of K(sub.i), the inhibition constant, and IC(sub.50), which represents the concentration of inhibi tor necessary to halve the reaction rate of an enzyme-catalyzed reaction seen under specified assay conditions, and the intuitive way of looking at the relationship are discussed with attention to a more general use for the Dixon plot and helping chemistry students understand the relationship . Design and synthesis of small-molecule enzyme inhibitors is of much interest inasmuch as finding a potent inhibitor of an enzyme related to a disease may bring access to a valuable pharmaceutical . Students must understand that the potency of different inhibitors of the same enzy me may not be compared by direc tly comparing K(sub.i) and IC(sub.50) values.

In this paper, protein-drug interactions were studied by solid-phase microextraction (SPME) using diazepam binding to human serum albumin as a model system. Since drug compounds are normally polar and nonvolatile by nature, direct SPME is used in this work. The SPME extraction is an equilibrium process among the concentrations of the analyte partitioned onto the SPME fiber, free and bound drug in the solution. A calibration curve was first constructed by employing the amount of the analytes partitioned on the fiber versus the free analyte concentration in the solution in the absence of protein. In method I, the extraction was performed in the protein solution with known diazepam concentration. In method II, diazepam was first loaded onto the fiber by extracting in solution with known diazepam concentration. This fiber was subsequently transferred into the protein solution for desorption. The amount of the analyte left on the fiber was analyzed after the system reached equilibrium. The free drug concentration was then obtained from the calibration curve for both methods. The Scatchard plot was finally employed to obtain the number of binding sites and the equilibrium binding constants. Since only a very small amount of the protein solution is required (150 [micro]L for each extraction), method II is very useful for circumstances where the protein amount is very limited. The direct measurement method proposed in this paper does not need a GC response factor, which significantly decreases the experimental error. The only measurement needed is the area count change (ratio) of the fiber injections before and after the protein was introduced into the solution. The difference between the direct measurement method for method I and method II is discussed. The result illustrated that the SPME direct measurement method provided both theoretical accuracy and simplicity in such applications.

Optimized suspension culture: the rotating-wall vessel. Am J Physiol Renal Physiol 281: F12-F25, 2001.--Suspension culture remains a popular modality, which manipulates mechanical culture conditions to maintain the specialized features of cultured cells. The rotating-wall vessel is a suspension culture vessel optimized to produce laminar flow and minimize the mechanical stresses on cell aggregates in culture. This review summarizes the engineering principles, which allow optimal suspension culture conditions to be established, and the boundary conditions, which limit this process. We suggest that to minimize mechanical damage and optimize differentiation of cultured cells, suspension culture should be performed in a solid-body rotation Couette-flow, zero-headspace culture vessel such as the rotating-wall vessel. This provides fluid dynamic operating principles characterized by 1) solid body rotation about a horizontal axis, characterized by colocalization of cells and aggregates of different sedimentation rates, optimally reduced fluid shear and turbulence, and three-dimensional spatial freedom; and 2) oxygenation by diffusion. Optimization of suspension culture is achieved by applying three tradeoffs. First, terminal velocity should be minimized by choosing microcarrier beads and culture media as close in density as possible. Next, rotation in the rotating-wall vessel induces both Coriolis and centrifugal forces, directly dependent on terminal velocity and minimized as terminal velocity is minimized. Last, mass transport of nutrients to a cell in suspension culture depends on both terminal velocity and diffusion of nutrients. In the transduction of mechanical culture conditions into cellular effects, several lines of evidence support a role for multiple molecular mechanisms. These include effects of shear stress, changes in cell cycle and cell death pathways, and upstream regulation of secondary messengers such as protein kinase C. The discipline of suspension culture needs a systematic analysis of the relationship between mechanical culture conditions and biological effects, emphasizing cellular processes important for the industrial production of biological pharmaceuticals and devices. laminar flow; bioproducts; microcarriers; shear; gene expression

Chemicals that can act as contact allergens have been identified successfully using guinea-pig models. However, contact allergy is still common, probably because of, at least in part, failures of risk assessment. A new method, the local lymph node assay, replaces the guinea-pig as a tool for hazard identification and offers the real prospect of accurate prediction of allergen potency, the missing link in skin sensitization risk assessment.

Protonated complexes involving cyclodextrin hosts and guest compounds that are pharmacologically important are produced in the gas phase and reacted with a gaseous amine. The guest is exchanged to produce a new protonated complex with the amine. The reaction is enantioselective and is used to develop a method for determining enantiomeric excess using only mass spectrometry. The pharmaceutical compounds include DOPA, amphetamine, ephedrine, and penicillamine. The presence of more than one reacting species is observed with DOPA and penicillamine. Molecular dynamics calculations are used to understand the nature of the interactions and the possible source of the variations in the reactivities.

Human tumor classification is a complex process currently based upon a complex mixture of empirically determined criteria. However, additional methods of classification would be helpful as tumors that are classified as being similar often have different clinical outcomes. Distinctive gene expression programs determine many of the structural, physiological and developmental characteristics that distinguish the hundreds of different kinds of normal cells in the human body, including the many cell types that superficially appear indistinguishable. By giving us a systematic way to observe and characterize gene expression programs, modern genomic analysis tools, such as DNA microarrays, show the promise of providing an unbiased and broad approach to detecting biologically relevant differences within morphologically similar tumors. In some early examples, distinctive gene expression patterns have provided detailed molecular portraits that can be related to clinically important variation in individual tumors. The likely impact of a molecular taxonomy of tumor subtypes based upon an objective study of tumors is discussed.

During the 20th century, a great deal of biological knowledge came from the perfection of methods to perform manipulative transmission genetics. During the early 21st century, such methods will be supplemented, and perhaps sometimes supplanted, by dominant `genetic' methods to probe the function of the proteome.

Most of our knowledge about the neuronal processes underlying brain functions comes from studies in which the activity of individual nerve cells is recorded with a microelectrode and analysed as a function of sensory stimulation, cognitive processes or motor behaviour. In spite of the undisputed success of this approach, many laboratories record simultaneously from a large number of neurones. This technically demanding strategy increases the amount of data that can be obtained from each experiment and hence contributes to the ethically desirable reduction of animal experiments. However, there is also a scientific motivation for the use of multi-electrodes. Increasing evidence suggests that the brain utilizes distributed codes that can only be analysed by measuring co-variations in amplitude and timing of simultaneously recorded neuronal responses.

Modern drug discovery often involves screening small molecules for their ability to bind to a preselected protein target. Target-oriented syntheses of these small molecules, individually or as collections (focused libraries), can be planned effectively with retrosynthetic analysis. Drug discovery can also involve screening small molecules for their ability to modulate a biological pathway in cells or organisms, without regard for any particular protein target. This process is likely to benefit in the future from an evolving forward analysis of synthetic pathways, used in diversity-oriented synthesis, that leads to structurally complex and diverse small molecules. One goal of diversity-oriented syntheses is to synthesize efficiently a collection of smart molecules capable of perturbing any disease-related biological pathway, leading eventually to the identification of therapeutic protein targets capable of being modulated by small molecules. Several synthetic planning principles for diversity-oriented synthesis and their role in the drug discovery process are presented in this review., Modern methods for stereoselective organic synthesis have increased the efficiency with which small molecules can be prepared. These compounds include new drugs and drug candidates and reagents used to explore [...]

Author(s): Bibi Bielekova (corresponding author) [1] [illus. 1] The economic and human cost of central nervous system (CNS) disorders is enormous [1], and neurodegenerative diseases such as progressive multiple sclerosis [...]

A new type of catalyst assembles cancer drugs from benign components, and can work inside laboratory animals. Some drug molecules can be split into smaller parts that are then equipped [...]

Author(s): Mark Frasier (corresponding author) [1] [illus. 1] The current rate of drug development for Parkinson's disease is unprecedented, aided by the discovery of genetic targets and by the creative [...]

In the past quarter of a century, a wave of drugs has transformed the treatment of depression. But the advances have struggled to come to grips with symptoms that often [...]

The past century has been a time of enormous growth in drug discovery. Synthetic organic chemistry plays a big part in this effort, but perhaps more important has been discovery [...]