Enzymes

Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions. The molecules at the beginning of the process are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life. The set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology.

Enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules. Enzymes' specificity comes from their unique three-dimensional structures.

Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy. Some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, and activators are molecules that increase activity. Many drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH.

Some enzymes are used commercially, for example, in the synthesis of antibiotics. Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, and enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.

  • Blut-Abbau im Akkord: Zell-Einwanderer schützen vor Eisenvergiftung

    Blut Abbau im Akkord Zell Einwanderer schützen vor Eisenvergiftung | Können Monozyten nicht in die Leber einwandern und sich zu Eisen-verwertenden Zellen entwickeln, lagert sich giftiges Eisen in Organen wie der Niere ab. (Eisen-frei: blau, Eisen-Protein-Komplex:braun) Abbildung: CSB Massachusetts General Hospital

    Freiburger Forscher entschlüsseln, wie der Körper rote Blutkörperchen abbaut, ohne sich dabei selbst zu vergiften. Der neue Ansatz könnte Komplikationen nach Blutvergiftungen und Hämolyse vermindern.

  • Bringing artificial enzymes closer to nature

    Representation of the new-to-nature olefin metathesis reaction in E. coli using a ruthenium-based artificial metalloenzyme to produce novel high added-value chemicals.

    Scientists at the University of Basel, ETH Zurich, and NCCR Molecular Systems Engineering have developed an artificial metalloenzyme that catalyses a reaction inside of cells without equivalent in nature. This could be a prime example for creating new non-natural metabolic pathways inside living cells, as reported today in Nature.

  • Cancer Research - How Cells Die by Ferroptosis

    A Fibroblast Undergoing Ferroptosis. Source: Helmholtz Zentrum München

    Ferroptosis is a recently discovered form of cell death, which is still only partially understood. Scientists at the Helmholtz Zentrum München have now identified an enzyme that plays a key role in generating the signal that initiates cell death. Their findings, published in two articles in the journal ‘Nature Chemical Biology’, could now give new impetus to research into the fields of cancer, neurodegeneration and other degenerative diseases. The term ferroptosis was first coined in 2012. It is derived from the Greek word ptosis, meaning “a fall”, and ferrum, the Latin word for iron, and describes a form of regulated necrotic cell death in which iron appears to play an important role.

  • Diabetesforschung: Neuer Mechanismus zur Regulation des Insulin-Stoffwechsels gefunden

    Die Abbildung zeigt das isolierte Nervensystem einer Drosophila Larve. Farblich markiert sind die Kerne jener Zellen, die das untersuchte Enzym produzieren. Foto: Universität Osnabrück

    OSNABRÜCK/KOPENHAGEN.- Insulin stellt ein für alle Wirbeltiere lebensnotwendiges Hormon dar, da es unter anderem die Körperzellen anregt, Glukose aus dem Blut aufzunehmen und somit den Blutzuckerspiegel zu senken. Eine fehlerhafte Regulation des Insulin-Stoffwechsels führt zu vielfältigen Krankheiten, wobei Diabetes die weltweit größte Verbreitung aufweist. Basierend auf dieser hohen medizinischen Relevanz arbeiten international zahlreiche Forschergruppen daran, Faktoren zu identifizieren, die den Insulin-Stoffwechsel regulieren. So auch an der Universität Osnabrück.

  • Die Blüte im Auge

    Was haben Walnussblätter, Champignons und die Blütenblätter des Mädchenauges gemeinsam? Sie enthalten große Mengen an jenen Enzymen, die auch für Bräunungsreaktionen in Bananen oder Äpfeln verantwortlich sind. ChemikerInnen der Uni Wien haben erstmals die Enzymstruktur in den Blütenblättern des Mädchenauges analysiert.

  • Doppelschlag gegen Bakterien und Viren

    Doppelschlag gegen Bakterien und Viren picture1 | Das Bakterium Staphylococcus aureus (rot) bildet häufig Resistenzen gegen Antibiotika aus und ist besonders für Patienten gefährlich, die bereits unter einer Infektion mit dem AIDS-Erreger HIV leiden Abbildung: HZI/M. Rohde

    Dualer Wirkstoff hemmt die Vermehrung des AIDS-Erregers HIV und von resistenten MRSA-Bakterien zugleich, indem er sowohl virale als auch baktrielle Enzyme hemmt.

  • Ein negatives Enzym liefert positive Resultate

    Ein negatives Enzym liefert positive Resultate Das Anion-π-Enzym besteht aus einem elektronenarmen Aren-Kofaktor (graue Stäbchenrepresentation), eingebettet in ein Protein (als Oberfläche dargestellt). Abbildung: Universität Basel, Departement Chemie

    In den letzten zwanzig Jahren hat die Chemie viele wichtige Instrumente und Verfahren für die Biologie hervorgebracht. Heute können wir Proteine herstellen, die in der Natur bisher nicht vorkommen. Es lassen sich Bilder von Ausschnitten lebender Zellen aufnehmen und sogar einzelne Zellen in lebendigen Tieren beobachten. Diese Woche haben zwei Forschungsgruppen der Universitäten Basel und Genf, die beide dem Nationalen Forschungsschwerpunkt Molecular Systems Engineering angehören, im Forschungsmagazin «ACS Central Science» präsentiert, wie man ein nicht-natürliches Protein designt, das völlig neue Fähigkeiten aufweist.

  • Elektrochemische Konzentrationsbestimmung von roten Blutkörperchen

    Elektrochemische Konzentrationsbestimmung von roten Blutkörperchen | Methode zur Kontrolle der Konzentration von roten Blutkörperchen Abbildung: Wiley-VCH

    Statt die roten Blutkörperchen wie üblich unter dem Mikroskop zu zählen, wurde ein elektrochemischer Ansatz entwickelt mit dessen Hilfe sowohl die Konzentration, als auch die Peroxidaseaktivität von Erythrozyten ermittelt werden kann.

  • Every atom counts in Protein structures

    Every atom counts in Protein structures | Tailored parallel X-rays perfectly matching the dimensions of the protein crystals enabled the scientists to determine the proteasome structure in unprecedented detail. Illustration: Hartmut Sebesse / Max Planck Institute for Biophysical Chemistry

    Malignant cancer cells not only proliferate faster than most body cells. They are also more dependent on the most important cellular garbage disposal unit, the proteasome, which degrades defective proteins. Therapies for some types of cancer exploit this dependence: Patients are treated with inhibitors, which block the proteasome. The ensuing pile-up of junk overwhelms the cancer cell, ultimately killing it. Scientists have now succeeded in determining the human proteasome’s 3D structure in unprecedented detail and have deciphered the mechanism by which inhibitors block the proteasome. Their results will pave the way to develop more effective proteasome inhibitors for cancer therapy.

  • Innovatives enzymatisches Verfahren zur Semisynthese von Taxanen

    Prinzip des Enzym-Membran-Kontaktors

    Das wissenschaftliche Ziel eines erfolgreich abgeschlossenen Projektes war die Entwicklung eines innovativen und nachhaltigen biotechnologischen Verfahrens zur Synthese des therapeutischen Wirkstoffs Taxol® und weiterer, an der Seitenkette modifizierter Taxane. Das technische Ziel dieses Projektes war die Entwicklung eines Membran-Kontaktors, welcher zur Synthese und in-situ Extrakti-on der Reaktionsprodukte genutzt wurde.

  • Nature communications: From the plant to the microreactor

    Carnosic acid is still obtained from rosemary. However, biotechnological production processes could be developed soon. Picture: IPB

    Scientists at the Leibniz-Institute of Plant Biochemistry (IPB) in Halle/Saale (Germany) have fully elucidated the biosynthesis of carnosic acid. This discovery allowed the plant researchers around Prof. Alain Tissier to produce the economically valuable plant material by biotechnological means in yeast cells. The project was published in the renowned journal Nature Communications.

  • New chemistry of life

    Lung tissue during legionellosis.

    FRANKFURT. The attachment of ubiquitin was long considered as giving the „kiss of death“, labelling superfluous proteins for disposal within a cell. However, by now it has been well established that ubiquitin fulfils numerous additional duties in cellular signal transduction. A team of scientists under the lead of Ivan Dikic, Director of the Institute of Biochemistry II at Goethe University Frankfurt, has now discovered a novel mechanism of ubiquitination, by which Legionella bacteria can seize control over their host cells. Legionella causes deadly pneumonia in immunocompromised patients. A novel ubiquitination mechanism explains pathogenic effects of Legionella infection. First results hint towards a broader role in regulating many life processes.

  • RUB-Forscher nutzen Cyanobakterien für Produktion von Chemikalien

    Bochumer Forscher haben Cyanobakterien so verändert, dass sie die Synthese wertvoller Feinchemikalien katalysieren. Die für die enzymatische Katalyse notwendige Energie produzieren die Mikroorganismen durch Fotosynthese selbst. Die Ergebnisse veröffentlichte das Team um Prof. Dr. Robert Kourist in der Zeitschrift „Angewandte Chemie“.

  • Scientists decode bacterial enzyme / Possible approach to tackle infections from hospital germs

    Microbiologists at the Universities of Münster and Nottingham, in England, have analysed an enzyme which might play an important role in the treatment of infections from the hospital germ pseudomonas aeruginosa. They have decoded the three-dimensional structure of the enzyme and revealed its function.

  • Selective manipulation of enzyme can stop cancer cachexia

    Healthy fat tissue is essential for extended survival in the event of tumor-induced wasting syndrome (cachexia). In Nature Medicine, researchers at Helmholtz Zentrum München show that selective manipulation of an enzyme can stop unwanted metabolic processes.

  • When fat cells change their colour

    The Freiburg researchers selectively ablated Lsd1 and inactivated its catalytic activity in brown adipocytes, which triggered a profound whitening of brown adipose tissue.

    The epigenetic enzyme Lsd1 plays an important role in maintaining brown fat tissue. In mammals, three types of adipose tissues exist. White adipocytes are mainly located in the abdominal and subcutaneous areas of the body and highly adapted to store excess energy. Conversely, beige and brown adipocytes are highly energy-expending by generating heat. A team with the Freiburg researchers Prof. Dr. Roland Schuele and Dr. Delphine Duteil has now shown that the epigenetic enzyme lysine-specific demethylase 1 (Lsd1) plays a key role in maintaining the metabolic properties of brown fat.

  • Why is the immune system unable to combat HIV? Key factor identified

    An international research group with essential participation of the Paul-Ehrlich-Institut, has identified NLRX1, a cellular factor of the human cell that is indispensable to the replication of Human Immunodeficiency Virus (HIV-1). This factor plays a key role in attenuating the innate immune system towards HIV-1. Until now, the significance of NLRX1 for the replication of HIV-1 and the attenuation of the immune system was not known. The novel research finding will lead to new therapeutic approaches. The research results are reported in Cell Host Microbe in its oedition of 13.04.2016

  • Wurzelsymbiose - Enge Freundschaft mit Kontrolle

    Die Symbiose mit Mykorrhiza-Pilzen verschafft Pflanzen einen besseren Zugang zu knappen Ressourcen. LMU-Forscher haben nun einen Mechanismus entdeckt, mit dem die Pflanze möglicherweise steuern kann, wie eng die Symbiose ist.