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.

  • A Boost for Biofuel Cells

    Boosting the energy output by storing and bundling the energy of many spontaneous enzyme reactions. Alejandro Posada

    In chemistry, a reaction is spontaneous when it does not need the addition of an external energy input. How much energy is released in a reaction is dictated by the laws of thermodynamics. In the case of the spontaneous reactions that occur in the human body this is often not enough to power medical implants. Now, scientists at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international team of researchers, found a way to boost the energy output by storing and bundling the energy of many spontaneous enzyme reactions. The work is published in the journal Nature Communications.

  • A Boost for Photosynthesis

    Cryo-EM structure of the linked complexes of CcmM (red) and Rubisco (green) in liquid droplets (yellow). Formation of this network is the first step in carboxysome biogenesis in cyanobacteria. Illustration: Huping Wang, Andreas Bracher © MPI of Biochemistry

    Photosynthesis is a fundamental biological process which allows plants to use light energy for their growth. Most life forms on Earth are directly or indirectly dependent on photosynthesis. Researchers at the Max Planck Institute of Biochemistry in Germany have collaborated with colleagues from the Australian National University to study the formation of carboxysomes – a structure that increases the efficiency of photosynthesis in aquatic bacteria. Their results, which were now published in Nature, could lead to the engineering of plants with more efficient photosynthesis and thus higher crop yields.

  • A Molecular Switch May Serve as New Target Point for Cancer and Diabetes Therapies

    Signal receptor-containing vesicles (red) form on the inside of the cell membrane (brown) and bud off into the cell. Visualization: Thomas Splettstößer

    If certain signaling cascades are misregulated, diseases like cancer, obesity and diabetes may occur. A mechanism recently discovered by scientists at the Leibniz- Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin and at the University of Geneva has a crucial influence on such signaling cascades and may be an important key for the future development of therapies against these diseases. The results of the study have just been published in the prestigious scientific journal 'Molecular Cell'.

  • 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.

  • Closing In On the Secret of Possible New Enzymes

    The Peter Comba Research Group. © University of Heidelberg

    Researchers at Heidelberg University have gained new knowledge on the possible biological function of patellamides. In laboratory experiments, they were able to demonstrate that this natural product displays important catalytic activity in combination with copper(II). The team of scientists headed by chemist Prof. Dr Peter Comba developed a special method to determine whether this activity can also be observed in the patellamide-producing organisms. This means that stable copper(II) patellamide complexes could be confirmed in living cells – which would imply that these compounds can act as catalysts.

  • Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke

    From laboratory to everyday life: Artificially produced copper hydroxide nanoparticles catalyze the decomposition of oxygen radicals by imitating a natural enzyme-induced catalytic defense mechanism. The integration of such nanoparticles in commercial cigarette filters can result in a reduction of the toxicity of cigarette smoke. Ill./©: Karsten Korschelt, AG Tremel, JGU

    Natural defense mechanism simulated with the help of nanoparticles / Noxious effects of smoke reduced.

    Chemists at Johannes Gutenberg University Mainz (JGU) have developed a technique that reduces the toxic effects of commercially available cigarettes. In spite of the fact that the World Health Organization (WHO) estimates that some 6 million people die every year as a consequence of tobacco consumption, the number of smokers around the world is on the rise. The number of tobacco-related deaths is equivalent to the fatality rate that would occur if a passenger plane were to crash every hour. According to figures published by the German Federal Statistical Office, the tobacco industry generated a turnover of around EUR 20.5 billion in 2016 through the sale of cigarettes in Germany alone.

  • Designer Cells: Artificial Enzyme can Activate a Gene Switch

    Artificial metalloenzyme penetrates a mammalian cell, where it accelerates the release of a hormone. This activates a gene switch which then leads to the production of a fluorescent indicator protein. University of Basel, Yasunori Okamoto

    Complex reaction cascades can be triggered in artificial molecular systems: Swiss scientists have constructed an enzyme than can penetrate a mammalian cell and accelerate the release of a hormone. This then activates a gene switch that triggers the creation of a fluorescent protein. The findings were reported by researchers from the NCCR Molecular Systems Engineering, led by the University of Basel and ETH Zurich.

  • 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.

  • EU funds research on biofuels and infectious diseases

    Salmolla. © Goethe University Frankfurt.

    FRANKFURT. Two ERC Advanced Investigator Grants of the European Research Council to the amount of € 2.5 million each are going to researchers at Goethe University Frankfurt. Biochemist and physician Professor Ivan Dikic and microbiologist Professor Volker Müller are very honoured that their pioneering research projects have been selected for this substantial financial support.

    Volker Müller is one of the leading microbiologists worldwide in the field of microbial metabolism of microbes that grow in the absence of oxygen. His project centres on the production of biofuels with the help of bacteria that can use carbon dioxide as feedstock.

  • 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.

  • How enzymes communicate

    Electro-chemical coupling through protein super complexes: The calcium channel (Cav2) delivers calcium ions (Ca2+) that activate the enzyme NO synthase (NOS) for generation of the messenger NO. Source: Bernd Fakler

    Freiburg scientists explain the cell mechanism that transforms electrical signals into chemical ones. The enzymes nitric oxide (NO) synthase (NOS1) and protein kinase C (PKC) play an important role in a variety of signal transfer processes in neurons of the brain, as well as in many cell types of other organs. Together with Prof. Dr. Bernd Fakler at the Institute of Physiology at the University of Freiburg, the scientists Dr. Cristina Constantin and Dr. Catrin Müller have shown for the first time that enzymes can be activated under physiological conditions through sole electrical stimulation of the cell membrane. Protein super complexes that rapidly transform electrical signals at the cell membrane into chemical signal processes inside the cell emerge through direct structural interaction of both enzymes with voltage-gated calcium channels. The researchers have presented their work in the current issue of the scientific journal Proceedings of the National Academy of Sciences (PNAS).

  • How to brew high-value fatty acids with brewer’s yeast

    A modified fatty acid synthase (illustrated schematically in the blue box on the basis of its synthetic properties) can induce short-chain fatty acid production in a yeast cell. Synthesis can be compared with a multistep industrial process. By means of targeted modifications to the natural synthesis, individual processes are accelerated or slowed down (green and red arrows) in order to trigger premature release of short-chain fatty acids.

    Researchers at Goethe University Frankfurt have succeeded in producing fatty acids in large quantities from sugar or waste containing sugar with the help of yeasts.

    FRANKFURT. Short-chain fatty acids are high-value constituents of cosmetics, active pharmaceutical ingredients, antimicrobial substances, aromas or soap. To date, it has only been possible to extract them from crude oil by chemical means or from certain plants, such as coconut, using a complex process. Research groups led by Professor Martin Grininger and Professor Eckhard Boles at Goethe University Frankfurt have now succeeded in producing such fatty acids in large quantities from sugar or waste containing sugar with the help of yeasts. The process is simple and similar to that of beer brewing.

  • 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.

  • Insights into closed enzymes

    Representation of electron density at the disulphide bond (yellow, between C56 and C163) and in its close vicinity. Prof. Michael Kovermann, University of Konstanz

    Scientists at the University of Konstanz and Umeå University in Sweden have arrived at a structural model of the enzyme adenylate kinase in its closed state.

    The adenylate kinase enzyme is crucial to managing the energy budget of cells, accelerating the biochemical process whereby energy is stored or released. The enzyme continuously changes between open and closed states. In its closed form, adenylate kinase is particularly active biochemically and thus able to accelerate the chemical reaction of “docked” molecules that it has encased like a clam. These are called ligands.