The discovery of the enzyme test for Rh antibodies.
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Coombs Test↗
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Results for “Enzyme discovery”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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[Experimental intestinal obstruction; discovery of bacterial enzymes in the lymph of the thoracic duct].
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Esterases↗
Discovery of AICAR Tfase inhibitors that disrupt requisite enzyme dimerization.
The discovery of a new class of aminoimidazole carboxamide ribonucleotide transformylase (AICAR Tfase) inhibitors through screening peptidomimetic libraries (>40,000 compounds) that act by inhibiting requisite enzyme dimerization is disclosed. In addition to defining key structural features of the lead compounds responsible for the activity, kinetic analysis of the remarkably small inhibitors established that they act as noncompetitive, dissociative inhibitors of AICAR Tfase with the prototypical lead (A1B3, Cappsin 1) exhibiting a K(i) of 3.1 +/- 0.3 microM. Thus, the studies define a unique approach to selectively targeting AICAR Tfase over all other folate-dependent enzymes, and it represents only one of a few enzymes for which inhibition achieved by disrupting requisite enzyme dimerization has emerged from screening unbiased combinatorial libraries.
Dimerization↗
Discovery and engineering of enzymes for new-to-nature photobiocatalysis.
Photobiocatalysis integrates enzymatic catalysis with photochemistry, enabling challenging radical transformations with high selectivity under mild conditions. Early developments in this field were largely driven by the discovery that enzyme-bound cofactors can form photoactive charge-transfer complexes with substrates, thereby initiating radical chemistry upon light irradiation. Recent advances, however, have substantially expanded the mechanistic landscape of photobiocatalysis through diverse mechanisms. This review summarizes major developments in photobiocatalysis reported since 2024. Rather than cataloging individual reactions, we focus on the fundamental mechanisms of radical generation and interception within enzyme active sites, and discuss how these mechanistic principles guide the discovery, engineering, and design of enzymes for new-to-nature photobiocatalysis.
Protein Engineering↗
Challenges in enzyme mechanism and energetics.
Since the discovery of enzymes as biological catalysts, study of their enormous catalytic power and exquisite specificity has been central to biochemistry. Nevertheless, there is no universally accepted comprehensive description. Rather, numerous proposals have been presented over the past half century. The difficulty in developing a comprehensive description for the catalytic power of enzymes derives from the highly cooperative nature of their energetics, which renders impossible a simple division of mechanistic features and an absolute partitioning of catalytic contributions into independent and energetically additive components. Site-directed mutagenesis has emerged as an enormously powerful approach to probe enzymatic catalysis, illuminating many basic features of enzyme function and behavior. The emphasis of site-directed mutagenesis on the role of individual residues has also, inadvertently, limited experimental and conceptual attention to the fundamentally cooperative nature of enzyme function and energetics. The first part of this review highlights the structural and functional interconnectivity central to enzymatic catalysis. In the second part we ask: What are the features of enzymes that distinguish them from simple chemical catalysts? The answers are presented in conceptual models that, while simplified, help illustrate the vast amount known about how enzymes achieve catalysis. In the last section, we highlight the molecular and energetic questions that remain for future investigation and describe experimental approaches that will be necessary to answer these questions. The promise of advancing and integrating cutting edge conceptual, experimental, and computational tools brings mechanistic enzymology to a new era, one poised for novel fundamental insights into biological catalysis.
Binding Sites↗
Searching for new allosteric sites in enzymes.
The discovery of new allosteric sites generates opportunities for the identification of novel pharmaceuticals and increases our understanding of basic biological processes. Increasingly, allosteric sites are being discovered in various families of proteins by several methods, paving the way for the development of entirely new classes of drugs with a wide range of chemotypes. New allosteric sites in enzymes have been discovered both incidentally and by directed means, and the mechanisms by which allosteric activation and inhibition occur at these sites have been investigated. By exploring recent structurally well-characterized examples, trends begin to emerge for both the modes of binding and mechanisms of inhibition.
Allosteric Site↗
Cellulose synthases and related enzymes.
The discovery of a large number of genes encoding cellulose synthases and related glycosyltransferases in plants has led to a renewed interest in the biosynthesis of cell-wall polysaccharides. A number of approaches, including virus-induced gene silencing have proven useful in the functional analysis of these genes. X-ray analysis of the structures of a few glycosyltransferases has led to the identification and confirmation of the role of conserved residues within this group of enzymes. Analysis of related enzymes has provided useful information on the possible domain organization of cellulose synthases and the requirement for at least two separate glycosyltransferase activities in the processive synthesis of sugar chains.
Cellulose↗
Recent progress towards the application of hyperthermophiles and their enzymes.
The discovery of extremophiles has drastically changed our understanding towards the diversity of life itself and the conditions under which it can be sustained. Extremophiles have evolved to withstand and multiply under the extremes of temperature, pressure, pH and salinity. Hyperthermophiles are the group that have adapted to high temperature; many have been found to grow at temperatures above the boiling point of water. This review focuses on recent advances in application-based research on hyperthermophiles and their thermostable enzymes.
Archaea↗
Sequence-dependent structural variations of hammerhead RNA enzymes.
The discovery of in vivo catalytic activity for the hammerhead RNA self-cleaving domain has led to the development of a new class of sequence-specific RNA endonucleases. Two such ribozymes have been synthesized using in vitro transcription with T7 polymerase and their structures have been studied by optical spectroscopy, nuclear magnetic resonance and nondenaturing gel electrophoresis. These data show the presence of a stable hairpin consisting of a double helical stem and a tetranucleotide loop in both RNA enzymes. Additional structure, with different stabilities, is also observed in both RNA enzymes. The half-lives for cleavage of the complementary RNA substrates by these two RNA enzymes have been previously shown to differ by a factor of 50. The data presented here suggest that this rate difference may be a result of the formation of catalytically inactive conformations in the RNA enzyme which interfere with formation of the enzyme-substrate complex.
Base Sequence↗
Molecular recognition of inositol polyphosphates by intracellular receptors and metabolic enzymes.
The discovery that inositol lipids are fundamentally involved in cell signalling has been one of the most significant recent advances in cell biology. In particular, there is now evidence that certain products of polyphosphoinositide metabolism play second messenger roles in most cells. Inositol 1,4,5-trisphosphate and perhaps inositol 1,3,4,5-tetrakisphosphate bind to specific receptors and regulate Ca2+ release from, and movement between, intracellular stores. The synthesis of novel analogues of these second messengers is now providing clues to the structural requirements at such receptors as well as for molecules with stability towards metabolic enzymes. Stefan Nahorski and Barry Potter discuss these developments with a view to future pharmacological intervention at these sites.
Animals↗
Phage display as a tool for protease ligand discovery.
Proteolytic enzymes have been implicated as the pathological agent in a number of disease states. For this reason proteases are attractive therapeutic targets. Phage display of peptide libraries can be used to identify peptides that may be used either directly as inhibitors or serve as leads in the generation of prodrugs and peptidomimetics.
Bacteriophages↗
Myeloperoxidase deficiency. Increased sensitivity for immunocytochemical compared to cytochemical detection of enzyme.
The discovery of hereditary deficiency of myeloperoxidase (MPO) in neutrophils and monocytes of affected individuals has been based on the absence of cytochemical staining in these peripheral blood cells. We report that an immunocytochemical method shows more sensitivity than either the benzidine or 4-chloro-1-naphthol cytochemical methods. In MPO-deficient subjects, immunocytochemistry detects a marked decrease, but not absence, of MPO.
Benzidines↗
A bacterial selection for the directed evolution of pyruvate aldolases.
A novel bacterial in vivo selection for pyruvate aldolase activity is described. Pyruvate kinase deficient cells, which lack the ability to biosynthetically generate pyruvate, require supplementation of exogenous pyruvate when grown on ribose. Supplementation with pyruvate concentrations as low as 50 microM rescues cell growth. A known substrate of the KDPG aldolases, 2-keto-4-hydroxy-4-(2'-pyridyl)butyrate (KHPB), also rescues cell growth, consistent with retroaldol cleavage by KDPG aldolase and rescue through pyruvate release. An initial round of selection against 2-keto-4-hydroxyoctonate (KHO), a nonsubstrate for wild-type aldolase, produced three mutants with intriguing alterations in protein sequence. This selection system allows rapid screening of mutant enzyme libraries and facilitates the discovery of enzymes with novel substrate specificities.
Aldehyde-Lyases↗
Neuropeptide-processing enzymes: applications for drug discovery.
Neuropeptides serve many important roles in communication between cells and are an attractive target for drug discovery. Neuropeptides are produced from precursor proteins by selective cleavages at specific sites, and are then broken down by further cleavages. In general, the biosynthetic cleavages occur within the cell and the degradative cleavages occur postsecretion, although there are exceptions where intracellular processing leads to inactivation, or extracellular processing leads to activation of a particular neuropeptide. A relatively small number of peptidases are responsible for processing the majority of neuropeptides, both inside and outside of the cell. Thus, inhibition of any one enzyme will lead to a broad effect on several different neuropeptides and this makes it unlikely that such inhibitors would be useful therapeutics. However, studies with mutant animals that lack functional peptide-processing enzymes have facilitated the discovery of novel neuropeptides, many of which may be appropriate targets for therapeutics.
Animals↗
Symposium on Enzyme Inhibition and Drug Discovery. Antwerp, Belgium, 6 November 1992. Abstracts.
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Animals↗
Choosing the right chromatographic support in making a new acetylcholinesterase-micro-immobilised enzyme reactor for drug discovery.
The aim of the present study was to optimize the preparation of an immobilized acetylcholinesterase (AChE)-based micro-immobilized enzyme reactor (IMER) for inhibition studies. For this purpose two polymeric monolithic disks (CIM, 3 mm x 12 mm i.d.) with different reactive groups (epoxy and ethylendiamino) and a packed silica column (3 mm x 5 mm i.d.; Glutaraldehyde-P, 40 microm) were selected as solid chromatographic supports. All these reactors were characterized in terms of rate of immobilization, stability, conditioning time for HPLC analyses, optimum mobile phase and peak shape, aspecific interactions and costs. Advantages and disadvantages were defined for each system. Immobilization through Schiff base linkage gave more stable reactors without any significant change in the enzyme behaviour; monolithic matrices showed very short conditioning time and fast recovery of the enzymatic activity that could represent very important features in high throughput analysis and satisfactory reproducibility of immobilization yield. Unpacked silica material allowed off-line low costs studies for the optimization of the immobilization step.
Acetylcholinesterase↗
Biological miracles and misadventures: identification of sensitization and asthma in enzyme detergent workers.
The discovery that the enzymes used in biological washing powders were asthma-causing sensitizers derived initially from the concern of an industrial physician as to the possibility of pulmonary damage due to the proteolytic nature of the material. This caused a search for possible cases of enzyme-related illness. Careful history-taking led to a hypothesis concerning sensitization and allergic illness which was supported experimentally by skin prick tests and inhalation challenge tests, and later by radioallergosorbent tests (RAST). It seems that the consequences of handling this potentially allergenic material as a fine powder had not been anticipated; and failure to analyze cases of sickness, to identify asthma, and to consider its workplace source had prevented its recognition elsewhere. Contributing to this failure was the pattern of development and manifestations of allergic illness, which seldom occurred in the workplace and was not confined to enzyme workers or atopics. In some cases the incidence of illness had been suppressed, or investigation prevented.
Asthma↗
Functional proteomics for the discovery of carbohydrate-related enzyme activities.
Carbohydrate metabolism is central to the growth and development of organisms. Thousands of genes that are believed to code for proteins that build and remodel saccharides have been uncovered by genome sequencing projects, thereby necessitating higher-throughput methods to delineate the chemical and biological functions of all these proteins. Recent methods discussed in this review have begun to address this problem by the design of new activity-based probes and mass-differentiated carbohydrate libraries. In addition, a comparative view of carbohydrate-related enzymes from all three branches of life has led to the discovery of unusual enzymes to simplify the synthesis of carbohydrates such as the sugar nucleotides required by glycosyltransferases.
Carbohydrate Metabolism↗