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This programme singles out 4 main properties of enzymes - specificity, catalytic power, flexibility and co-operativity. Professor Koshland explains his idea of enzyme flexibility and explores some ...of its consequences for biochemistry. The programme concludes with a discussion of the property of co-operativity in terms of the flexible enzyme idea.
Metadata describing this Open University video programme
Module code and title: S322, Biochemistry and molecular biology
Item code: S322; 05
First transmission date: 05-05-1977
Published: 1977
Rights Statement:
Restrictions on use:
Duration: 00:24:00
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Producer: Andrew Crilly
Contributor: Daniel Koshland
Publisher: BBC Open University
Keyword(s): `Lock and key' model; Catalytic power; Co-operativity; Feedback; Flexibility; Induced fit; Inhibition; Specificity
Footage description: Professor Koshland introduces the programme. He lists four paramount properties of enzymes. With the aid of an atomic model of lysosyme and animated diagrams, Koshland discusses the early attempt, by Emil Fiscber, to account for these properties of enzymes with his template theory. Koshland points to some experiments which threw doubt on this theory and led him to postulate the induced fit theory. Koshland refers to diagrams on a blackboard, as he talks. Koshland goes on to explain why biological systems must be so efficient in their enzyme reactions, particularly as many involve a series of steps. He writes on a blackboard as he talks. Continuing to write on his blackboard and using also an animation, Koshland explains how his induced fit theory accounts for the phenomenon of feedback inhibition where the final product of a chain of reactions inhibits the first enzyme of the reaction. Koshland discusses another example of flexibility in enzyme control stemming from the role of hormones which control the path of glucose either for storage or for degradation. Animated diagrams help to illustrate points. Koshland, writing on a blackboard, explains how feedback information from the outside environment or from different parts of an organism is controlled at the molecular level by alterations in protein structure of the individual system. An animated diagram shows three possible conformational changes. Again writing and drawing on a blackboard, Koshland explains how Bohr discovered the co-operative phenomenon while studying saturation of haemoglobin with an oxygen substrate. He goes on to explain, briefly, how this concept was then applied to other molecules, particularly enzymes involved in regulation. A graph and diagrams illustrate points made.
Master spool number: 6HT/72543
Production number: 00525_1262
Videofinder number: 1011
Available to public: no