1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. SEP-SBI091-CP1-01 Introduction Programmes and Courses SEP–SBI091-U01-CP_01 2© 2008, YCMOU. All Rights Reserved.

3. School of Science and Technology, Online Counseling Resource… Credits  Academic Inputs by Sonali Alkari Faculty YCMOU Nagpur Centre, Faculty LAD college P.G. D of Biotechnology Research officer Ankur Seeds Pvt Ltd sonalisa_alkari@yahoo.co.in Sonalisaal@rediffmail.com 3© 2008, YCMOU. All Rights Reserved.

4. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to : Describe Enzymes Discuss historical Aspects of Enzymology; Role of enzymes as biocatalysts

6. School of Science and Technology, Online Counseling Resource… Introduction:Enzymes-1  Living systems make use of energy from the environment. Many of us, for example, consume substantial amounts of sucrose— common table sugar—as a kind of fuel, whether in the form of sweetened foods and drinks or as sugar itself.  The conversion of sucrose to CO 2 and H 2 O in the presence of oxygen is a highly exergonic process, releasing free energy that we can use to think, move, taste, and see.  However, a bag of sugar can remainon the shelf for years without any obvious conversion to CO 2 and H 2 O. © 2008, YCMOU. All Rights Reserved.6

7. School of Science and Technology, Online Counseling Resource… Introduction:Enzymes-2  Although this chemical process is thermodynamically favorable, it is very slow!.  Yet when sucrose is consumed by a human (or almost any other organism), it releases its chemical energy in seconds.  The difference is catalysis.  Without catalysis, chemical reactions such as sucrose oxidation could not occur on a useful time scale, and thus could not sustain life.  The reaction catalysts of biological systems: the enzymes, the most remarkable and highly specialized proteins. © 2008, YCMOU. All Rights Reserved.7

8. School of Science and Technology, Online Counseling Resource… Introduction: Enzymes-3  Enzymes have extraordinary catalytic power, often far greater than that of synthetic or inorganic catalysts.  Enzymes, the catalysts of biological systems, are remarkable molecular devices that determine the patterns of chemical transformations.  Enzymes mediate the transformation of one form of energy into another.  The most striking characteristics of enzymes are their catalytic power and specificity.  Catalysis takes place at a particular site on the enzyme called the active site.  Nearly all known enzymes are proteins. 8© 2008, YCMOU. All Rights Reserved.

9. School of Science and Technology, Online Counseling Resource… Role of Enzymes  Enzymes play a critical role in everyday life.  Many heritable genetic disorders (diabetes, Tay- Sachs disease) occur because there is a deficiency or total absence of one or more enzymes. Other disease conditions (cancer) result because there is an excessive activity of one or more enzymes.  Routine medical tests monitor the activity of enzymes in the blood, and many of the prescription drugs (penicillin, methotrexate) exert their effects through interactions with enzymes.  Enzymes and their inhibitors can be important tools in medicine, agriculture, and food science. © 2008, YCMOU. All Rights Reserved.9

10. School of Science and Technology, Online Counseling Resource… Enzymes as Biocatalysts-1  They have a high degree of specificity for their substrates, they accelerate chemical reactions tremendously, and they function in aqueous solutions under very mild conditions of temperature and pH.  Enzymes are central to every biochemical process.  Acting in organized sequences, they catalyze the hundreds of stepwise reactions that degrade nutrient molecules, conserve and transform chemical energy and make biological macromolecules from simple precursors. © 2008, YCMOU. All Rights Reserved.10

11. School of Science and Technology, Online Counseling Resource… Enzymes as Biocatalysts-2  Through the action of regulatory enzymes, metabolic pathways are highly coordinated to yield a harmonious interplay among the many activities necessary to sustain life.  In some diseases, especially inheritable genetic disorders, there may be a deficiency or even a total absence of one or more enzymes.  For other disease conditions, excessive activity of an enzyme may be the cause.  Measurements of the activities of enzymes in blood plasma, erythrocytes, or tissue samples are important in diagnosing certain illnesses. © 2008, YCMOU. All Rights Reserved.11

12. School of Science and Technology, Online Counseling Resource… Enzymes as Biocatalysts-3  Many drugs exert their biological effects through interactions with enzymes.  Enzymes are important practical tools, not only in medicine but in the chemical industry, food processing, and agriculture.  In many biochemical reactions, the energy of the reactants is converted with high efficiency into a different form.  For example, in photosynthesis, light energy is converted into chemical-bond energy through an ion gradient.  Enzymes may then use the chemical-bond energy of ATP in many ways © 2008, YCMOU. All Rights Reserved.12

13. School of Science and Technology, Online Counseling Resource… Enzymes as Biocatalysts-4  In mitochondria, the free energy contained in small molecules derived from food is converted first into the free energy of an ion gradient and then into a different currency, the free energy of adenosine triphosphate.  The enzyme myosin converts the energy of ATP into the mechanical energy of contracting muscles.  Pumps in the membranes of cells and organelles, which can be thought of as enzymes that move substrates rather than chemically altering them, create chemical and electrical gradients by using the energy of ATP to transport molecules and ions. © 2008, YCMOU. All Rights Reserved.13

14. School of Science and Technology, Online Counseling Resource… Historical Aspects of Enzymology-1  Much of the history of biochemistry is the history of enzyme research.  Biological catalysis was first recognized and described in the late 1700s, in studies on the digestion of meat by secretions of the stomach, and research continued in the 1800s with examinations of the conversion of starch to sugar by saliva and various plant extracts.  In the 1850s, Louis Pasteur concluded that fermentation of sugar into alcohol by yeast is catalyzed by “ferments.” © 2008, YCMOU. All Rights Reserved.14

15. School of Science and Technology, Online Counseling Resource… Historical Aspects of Enzymology  He postulated that these ferments were inseparable from the structure of living yeast cells; this view, called vitalism, prevailed for decades.  Then in 1897 Eduard Buchner discovered that yeast extracts could ferment sugar to alcohol, proving that fermentation was promoted by molecules that continued to function when removed from cells.  Frederick W. Kühne called these molecules enzymes.  The isolation and crystallization of urease by James Sumner in 1926 provided a breakthrough in early enzyme studies. 15© 2008, YCMOU. All Rights Reserved.

16. School of Science and Technology, Online Counseling Resource… Historical Aspects of Enzymology-3  Sumner found that urease crystals consisted entirely of protein, and he postulated that all enzymes are proteins.  In the absence of other examples, this idea remained controversial for some time.  Only in the 1930s was Sumner’s conclusion widely accepted, after John Northrop and Moses Kunitz crystallized pepsin, trypsin, and other digestive enzymes and found them also to be proteins.  The molecular nature of enzymes was not yet fully appreciated. © 2008, YCMOU. All Rights Reserved.16

17. School of Science and Technology, Online Counseling Resource… Historical Aspects of Enzymology-4  Haldane made the remarkable suggestion that weak bonding interactions between an enzyme and its substrate might be used to catalyze a reaction.  This insight lies at the heart of our current understanding of enzymatic catalysis.  Since the latter part of the twentieth century, research on enzymes has been intensive.  It has led to the purification of thousands of enzymes, elucidation of the structure and chemical mechanism of many of them, and a general understanding of how enzymes work. © 2008, YCMOU. All Rights Reserved.17

18. School of Science and Technology, Online Counseling Resource… What You Learn…  You have learnt : Enzymes, the catalysts of biological systems, are remarkable molecular devices that determine the patterns of chemical transformations. Nearly all known enzymes are proteins. Acting in organized sequences, they catalyze the hundreds of stepwise reactions that degrade nutrient molecules, conserve and transform chemical energy and make biological macromolecules from simple precursors. 18© 2008, YCMOU. All Rights Reserved.

19. School of Science and Technology, Online Counseling Resource… Critical Thinking Questions 1.What are enzymes? 2. Who has coined the term enzyme and why? 3.Summarize the historical aspects of enzymology? © 2008, YCMOU. All Rights Reserved.19

20. School of Science and Technology, Online Counseling Resource… Hints For Critical Thinking Question 1.Enzymes, the catalysts of biological systems, are remarkable molecular devices that determine the patterns of chemical transformations. 2.Frederick W. Kühne based on activity. 3.“ferments”, Eduard Buchner discovery, Frederick W. Kühne, isolation and crystallization and a general understanding of how enzymes work. © 2008, YCMOU. All Rights Reserved.20

21. School of Science and Technology, Online Counseling Resource… Study Tips:1  Book1 Title: Molecular Cell Biology Author: Harvey Lodish, David Baltimore Publisher:Publishers: W. H. Freeman and Company  Book2 Title: Principles of Biochemistry Author: AlbertL Lehninger Publisher:CBS Publishers & Distributors 21© 2008, YCMOU. All Rights Reserved.

22. School of Science and Technology, Online Counseling Resource… Study Tips:2  Book3 Title: Biochemistry Author: Lubert stryer Publishers: Freeman International  Book4 Title: Biochemistry Author: Keshav Trehan Publishers: Wiley Eastern 22© 2008, YCMOU. All Rights Reserved.

23. School of Science and Technology, Online Counseling Resource… Study Tips www.en.wikipedia.org Microsoft Encarta Encyclopedia http://en.wikipedia.org/wiki/ Wikipedia the free encyclopedia (www.chem.qmul.ac.uk/iubmb/enzyme). 23© 2008, YCMOU. All Rights Reserved.

24. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.24 End of the Presentation Thank You!