IMMOBILIZED ENZYMES FOR INDUSTRIAL APPLICATIONS
TABLE OF CONTENTS
1.2 Classification of Enzymes
1.3 Factors affecting enzymes activities
1.4 Kinetic of Enzymes catalyzed reactions
2.0 Immobilization process
2.1 Immobilized Enzymes
2.2 Immobilization techniques and support materials
2.3 Inhibition of Enzymes
2.4 Enzymes Mechanisms
3.0 Industrial Applications of Immobilized Enzymes
3.1 Immobilized Enzymes in Food Processing
3.2 Immobilized Enzymes in Clinical / Medical Industry
3.3 Immobilized Enzymes in drug design
3.4 Immobilized as Biosensors
3.5 Immobilized Enzymes in the production of Syrups from cornstarch (part of food application)
Future Role of Enzyme Immobilization
The history of enzymes may be regarded as commencing with the work of Dubrunfaut, (1830) who prepared malt extract from germinating barley seeds. This extract possessed the power of converting starch into sugar. Therefore, it is imperative to briefly discuss the general facts and concepts of Enzymes before passing to detailed study of the various applications of immobilized enzymes in industries.
1.1 Enzymes: These can be defined as the substances which catalyzing or alter the rate of chemical reactions. All enzymes are conjugated proteins and usually associated with non – proteins groups. The catalytic activities depend on the maintenances of their native structure and slight variations may result in significant changes in their activities. A common feature of all enzymes in the presence of a cleft / depression in the structure which is line mainly with hydrophobic amino acids into which the substrate fixed which is known as the ‘Active site’. Certain amino acids residues which are concern with either orientation of the concentrate and the ends with the specificity of the enzymes or are involved in the catalyst of the reaction are located in this cleft, those amino acid that are associated with the latter role form the active site of the enzymes and are often located towards its base of this cleft, those amino acid that are associated with the latter role form the active site of the enzyme and are often located towards its base of this cleft. In most cases, they are ionic or reactive and they include instidine, serine as well as Glutaric and Asphatic acid. In addition, the Ions from a solution particularly cations may aid either location of substrate of the reaction. (Extracted from fundamentals of the biochemistry 6th Ed. S. ched & Co Ltd. New Delhi. Pg. 334 -348)
1.2 CLASSIFICATION OF ENZYMES
Enzymes can be classified according to their catalytic actions on various compounds.
⦁ Oxidoreductases: these catalyze the transfer of hydrogen or oxygen atoms or electrons and are using NAD+/NADP+ as an electron acceptor.
⦁ Transferases: catalyze the specific grouping transferring e.g. Methyl, Carbonyl and COA.
⦁ Hydrolyses: catalyze transfer of hydrolytic reactions e.g carbonsilic ester, thiolester, endoribonuclear and dipeptile hydrolyses.
⦁ Liases: these are enzymes that catalyze cleaving of bones by reaction.
⦁ Isomerizes: these catalyze intra molecular rearrangements.
⦁ Ligases: catalyses formation of bones and required ATP.
1.3 FACTORS AFFECTING ENZYMES ACTIVITIES
1. TEMPERATURE: An increase in temperature of an enzymes increase the rate of all chemical reactions include those catalyze by the enzymes, it also increases the rate of denaturation of enzymes proteins, denaturation occur more readily.
Denaturation Increase reaction rate
Table 1.31 Temp. (oo)
EFFECT OF TEMPERATURE ON ENZYMES
Because of denaturation of A, the proportion of active fall and these two processes result in deducted line.
2. PH: All enzymes are sensitive to changes in P.H and function best over a very limited range with a definite P.H optimum. The effects of P.H are to the changes in the tonic state of both amino acid residues of the enzymes and substrate molecules.
There alterations incharge will affect substrate bonding and the resulting rate of the reaction over a narrow P.H range, this effect will be reversible but extreme acidity or alkalinity often cause serious distortion of protein structure and result in permanent denaturation.
TABLE 1.32 EFFECT OF P.H ON ENZYME LACTATE.
3. SUBSTRATE CONCENTRATION: If concentration is at low substrate, the rate of reaction increases and at higher concentration the rate begins to level out and eventually becomes almost constant regardless other increase of concentration.
4. KINETIC OF ENZYMES CATALYZED REACTIONS
The law of mass action states that, the rate of chemical reaction is proportional to the product of concentration of the reaction. These means that the rate of reaction which has a style component will increase in direct relation to the increase in concentration but for a two component reaction, the two will increase in proportion to the square of concentration.
These relationships may be express in the following term.
Rate = k1 (concentration) ___ style
Rate = k2 (concentration x (concentration) two reactions
Where k1, and k2 are reaction velocity concentration or the rate constant for the reaction. The reactions are said to show first and second order kinetic respectively, occasional situation may arise where the cases on the concentration of a reactant do not result in an increased reaction rate, such reaction are said to be zero order kinetic.
The effect of increase the concentration of substrate can be explain most satisfactorily by the formation of an enzyme substrate complex as a key state of reaction.
Approximately first order kinetic
It is the breakdown of the complex which result in the formation of the product and hence first order kinetic applied. The profile shows the effect of enzymes on the action at low concentration, the rate of resulting from the first order and of the enzyme id proportional to the concentration of the reaction.
However, at high concentration the reaction is almost constant and independent of the substrate concentration.
[Extracted from Jain I.L (Jain S and Jain N. (2005); fundamental of biochemistry. 6th Ed. S chand & co. ltd. New Delhi pg. 334.-348].