Botany lecture notes

Enzymes in Plant Pathogenesis (Host Parasite Interactions-Part I)

Host Parasite Interactions

(Plant-Pathogen Interaction Part I: Enzymes in Plant Pathology)

What are the enzymes involved in pathogenesis (plant pathology)?

Most of the fungal and bacterial parasites produce many enzymes that degrade the plant materials in vivo. Enzymes involved in pathogenesis or virulence (process of disease initiation) includes both constitutive and inducible enzymes.

(1). Constitutive enzymes are those enzymes which are present all the time in the cells.

(2). Inducible enzymes are those enzymes which are produced only when they are needed by the cells in response to certain internal or external stimuli.

Important classes of enzymes involved in pathogenesis are:

(1). Cutinases

(2). Pectinases

(3). Cellulases

(4). Hemicellulases

(5). Ligninases

(6). Lipases

(7). Proteinases

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biological chemistry

Enzyme Regulation Mechanisms: The Molecular Methods to Regulate Enzymes and Enzymatic Acitvity

what are regulatory enzymes

What are enzymes?

Ø  All living organisms in the world should possess TWO fundamental properties

Ø  They are:

(1). Must be able to self-replicate

(2). Must be able to catalyze chemical reactions efficiently and selectively

Ø  Enzymes are the molecules which enables each living entity to do these two fundamental activities

Ø  Enzymes are better known as biological catalysts

Ø  Almost all enzymes are highly specialized proteins

Ø  Ribozymes: RNA molecules with catalytic properties

Ø  Abzymes: antibodies with catalytic properties

What is enzyme regulation?

Ø  Enzyme regulation definition: “Process, by which cells can turn on, turn off, or modulate the activities of various metabolic pathways by regulating the activity of enzyme”

Ø  Enzymes have extraordinary catalytic power

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biological chemistry

Enzyme Specificity (Biochemistry Lecture Notes)

Biochemistry of Enzyme Substrate Specificity and its Classification With Examples

.“There is more to life than increasing its speed…”

                                                                                    Mahatma Gandhi

Enzymes are biological catalysts. They accelerate the rate of metabolic reactions in the cells by reducing the activation energy of the reactants. Almost all enzymes are specialized proteins with definite structural conformations.

Important characteristic features of enzyme are:

1. Catalytic Power (ratio of enzyme catalyzed rate of a reaction to the un-catalyzed rate)

2. Regulation (control of enzymatic reaction)

3. Specificity (Selectivity of enzyme to their substrate)

What is enzyme specificity?

Specificity is the ability of an enzyme to choose exact substrate from a group of similar chemical molecules. The specificity is actually a molecular recognition mechanism and it operates through the structural and conformational complementarity between enzyme and substrate. Enzymes show different degrees of specificity towards their substrate.

how enzyme and substrate binds .. conformational asymmetry of enzyme and substrate

The specificity shown by enzymes are grouped into 6 categories

1.  Bond specificity

2.  Group specificity

3.  Substrate specificity

4.  Stereo specificity (Optical specificity)

5.  Geometrical specificity

6.  Co-factor specificity

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Biotechnology Lecture Notes

Enzyme Immobilization Methods and Applications (Biotechnology Lecture Notes)

Methods & Applications of Enzyme & Whole Cell Immobilization
(Advantages and Disadvantages of Enzyme Immobilization; Matrix/Supports Used in Enzyme Immobilization)

What is enzyme immobilization?

Immobilization is defined as the imprisonment of cell or enzyme in a distinct support or matrix. The support or matrix on which the enzymes are immobilized allows the exchange of medium containing substrate or effector or inhibitor molecules. The practice of immobilization of cells is very old and the first immobilized enzyme was amino acylase of Aspergillus oryzae for the production of L-amino acids in Japan. 

Advantages of immobilized enzymes:

(1).   Increased functional efficiency of enzyme

(2).   Enhanced reproducibility of the process they are undertaking

(3).   Reuse of enzyme

(4).   Continuous use of enzyme

(5).   Less labour input in the processes

(6).   Saving in capital cost and investment of the process

(7).   Minimum reaction time

(8).   Less chance of contamination in products

(9).   More stability of products

(10). Stable supply of products in the market

(11). Improved process control

(12). High enzyme substrate ratio

Disadvantages of enzyme immobilization:

(1).  Even though there are many advantages of immobilized enzymes, there are some disadvantages also.

(2).  High cost for the isolation, purification and recovery of active enzyme (most important disadvantage)

(3).  Industrial applications are limited and only very few industries are using immobilized enzymes or immobilized whole cells.

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