Artificial enzymes

Artificial enzymes

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  ARTIFICIAL ENZYMES Under theguidance of: •Dr. M. Murali Krishna •Dept of Pharmaceutical Chemistry AU COLLEGEOF PHARMACEUTICAL SCIENCES, VISAKHAPATNAM • Presented By: • Gandham Malasree • Regd no: 620209502002 • Dept of Pharmaceutical Chemistry
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  enzyme • Enzymes arebiological catalysts. • A Catalyst is defined as "a substance that increases the rate of a chemical reaction without being itself changed in the process.” Enzymes as Biological Catalysts: • Enzymes are proteins that increase the rate of reaction by lowering the energy of activation. • They catalyze nearly all the chemical reactions taking place in the cells of the body . • Enzymes have unique three-dimensional shapes that fit the shapes of reactants (substrates ).
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  PROPERTIESOFENZYMES • Catalytic efficiency– high efficiency, 103 to 1017 faster than the corresponding catalyzed reactions. • Specificity - high specific specificity, interacting with one or a few specific substrates and catalyzing only one type of chemical reaction. • Mild reaction conditions- 37℃, physiological pH, ambient atmospheric pressure.
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  Artificial enzymes  Artificialenzymes may be defined as the synthetic, organic molecule prepare to recreate/mimic the active site of an natural enzyme.  The binding of a substrate close to functional groups in the enzyme causes catalysis by so called proximity effects.  It is therefore possible to create similar catalysts from small molecule which will mimics the enzyme active sites.  Since the artificial enzymes need to bind molecules, they are made based on the host molecule such as cyclodextrins, crown ethers or calixarene etc.  They have a molecular weight less than 2000 Dalton.  They have the ability to stabilize at high temperature.  They are also known as synzymes or enzyme mimics.
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  EXAMPLES:  XNAzymes arecapable of cutting and joining strands of RNA in a test tube. These are used in the treatment of various diseases like cancer and viral infections. These are not recognized by bodys natural degrading enzymes as they are extremely robust.  Manganese dioxide(Mn3O4) ROS (reactive oxygen species ) scavenging activities have been developed for in vivi anti – inflammation.  Vanadium pentoxide mimics to glutathione peroxide.
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  IDEALCHARACTERISTICS OF ARTIFICIALENZYMES Hydrogenbonding and/or electrostatic binding sites complementary to the substrate. Catalytic group attached to the model. Rigid structure model. Water soluble and catalytically active under physiological conditions. Reversable, non-covalent binding with the release slower than the binding.
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  Need of artificialenzymes: • Tunable structures and catalytic efficiencies similar to natural enzymes. • Excellent tolerance to experimental conditions. • Purely synthetic routes for their preparation. • High cast and low stability limit the applications of natural enzymes. • Speeds up the reaction at a relatively high rate.
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  DESIGNAPPROACH FOR ARTIFICIALENZYME Two types of approaches used to develop artificial enzymes. 1.Chemical approach: • Cyclodextrins as enzyme mimics • Cyclophane as enzyme mimics • Calixarene as enzyme mimics • Crown ethers as enzyme mimics 2.Biological approach: • Direct evolution method for artificial enzyme production • De novo computational enzyme designing
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  Cyclodextrins: The three mostcommon cyclodextrins are , α- ,β-,and γ-species, which are composed of six, seven, and eight glucopyranose units, respectively. Hydrophobic cavity. Stable and water soluble. Tunable (modify to change properties) Research on cyclodextrin started in1930s very expensive &thought to be toxic 1970s – non toxic.
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  DIRECT EVOLUTIONMETHOD FORARTIFICIAL ENZYME PRODUCTION oDirect evolution is a molecular biology method to modify biocatalysts via in vitro version of “Darwinian evolution”. oDirect evolution provide improved enzymatic activity, thermostability, tolerance to organic solvent, substrate specificity, enantioselectivity and so on. Gene mutagenesis Insertion into host Transformed colony Eg: Sitagliptin
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  Insertion of gene sequenceinto host cell Transformed colony plating Bacteria producing mutant ezymes Screening for transformed colonies Evaluate by using enzymatic assays Gene mutagenesis More production of transformed colonies Eg: SITAGLIPTIN – it is used to treat patients with type 2 diabetes and high blood pressure
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  De Novo ComputationalEnzyme Designing  Under this automated identification of amino acid sequences performed that will fold into a specified three-dimensional structures. This method has emerged as a promising tool for engineering enzymes .  Conformational changes are part of the repertoire that natural enzymes use to catalyze reactions.  In order to select candidates sequences for enzymes at each step of the identified pathways, several tools provide different solutions, including anti SMASH for biosynthetic gene clusters. Tools used: • Path pred • RDM patterns • Bond-Electron matrices • Reactions SMARTS in Retro • Path 2.0
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  Ideal Environment RequirementFor Artificial Enzymes  The covalent immobilization of one enzyme on solid supports having large surfaces with given properties (eg., hydrophilic or hydrophobic surfaces) should provide a nano environment surrounding the area of the enzyme directly in contact with the support.  Further covalent immobilization of macromolecular polymers (hydrophilic, hydrophobic) on the same large internal surfaces of the solid support should provide an additional nano environment surrounding the area of the immobilized enzyme molecules next to the support.  Chemical modification of immobilized enzymes with polyfunctional macromolecules could also be an interesting way to greatly modified the enzyme nano environment with minimal chemical modification of the enzyme.
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  APPLICATIONS • Tunable structureand catalytic efficiencies similar to natural enzymes. • Excellent tolerance to experimental conditions. • Purely synthetic routes for their preparation. • Lower cost. Pharmaceutical : synthetic enzymes that accelerates the formation of drugs and chemicals. Medicine : use of synthetic enzymes as supplements for patients deficient in certain enzyme can be made instead of extracting natural enzymes from other organisms. Genetic Engineering : potentially designing synthetic enzymes that manipulate gene sequences to create genetically modified organisms or to help genealogy research.