this video describes the introduction about enzymes and nomenclature of enzymes. it explains IUB system of classification of Enzyme fully. it also explains the different classes of enzymes and enzyme commission number. https://youtu.be/JZOx9v1V7mA you tube link for lecture

1. Enzymes
BY: Dr. Sunita Sangwan
Assistant Prof. Dept of Botany,
Govt. college Bhiwani, Haryana

2. Content
• Basics of Enzymology
• Discovery and nomenclature
• Characteristics of enzymes
• Concept of Holoenzyme, apoenzyme,
coenzyme and co-factors
• Mechanism of action
• Enzyme Inhibition

3. Basics of Enzymology
• An enzyme is a biocatalyst that increase the
rate of chemical reaction without itself being
changed in the overall process.
• Unique properties of enzymes:
 Most of enzymes are proteins.
 Enzymes are highly specific.
 Enzymes exhibit enormous catalytic power.

4. Discovery of Enzymes
• Biological catalysis was first recognized and described in
the early 1800 s. in studies of the digestion of meat by
secretions of the stomach and the conversion of starch
into sugar by saliva and various plant extracts.
• The word itself means 'in yeast' and is derived from the
Greek 'en' meaning 'in', and 'zyme' meaning 'yeast‘ . This
important achievement was the first indication that
enzymes could function independently of the cell.

5. In 1835, Swedish chemist Jon Jakob Berzelius termed their
chemical action as catalytic in nature.
In 1860 Louis Pasteur recognized that enzymes were essential to
fermentation but assumed that their catalytic action was inextricably linked
with the structure and life of the yeast cell.
1897 it was shown by German chemist Edward Buchner that cell-free
extracts of yeast could ferment sugars to alcohol and carbon dioxide,
Buchner denoted his preparation as zymase.
In 1876, William Kuhne proposed that the name 'enzyme' be used as the
new term to denote phenomena previously known as 'unorganised ferments‘.

6. 1st enzyme isolated ?
• However, the first enzyme was obtained in pure
form in 1926, by American biochemist James B.
Sumner of Cornell University. Sumner was able to
isolate and crystallize the enzyme urease from the
jack bean.
• His work was to earn him the 1947 Nobel Prize.
John H. Northrop and Wendell M. Stanley of the
Rockefeller Institute for Medical Research shared
the 1947 Nobel Prize with Sumner.

7. Nomenclature of
Enzymes

8. Nomenclature of Enzymes
• The nomenclature of enzymes has undergone many
changes over the years
• The names assigned to enzymes in the beginning were
very vague and uninformative
• Some of the early names are pepsin, ptylin, zymase
etc.These indicate neither the substrates nor the type of
reaction catalyzed by the enzyme
• Later on, a slightly more informative nomenclature was
adopted.
• Suffix -ase was added to the name of the substrate e.g.
lipase, protease etc
• Still the type of reaction catalyzed by the enzyme

9. • Nomenclature was modified further, to include the name of the
substrate followed by the type of reaction ending with –ase.
• This resulted in names like lactate dehydrogenase, pyruvate
carboxylase, glutamate decarboxylase etc.
• Even these names do not give complete information, for example
whether a coenzyme is required or a byproduct is formed.
• To make the names of enzymes informative and unambiguous,
International Union of Biochemistry (IUB) formed an Enzyme
Commission.
• The enzyme commission proposed a method of nomenclature

10. According to IUB system
• The enzymes have been divided into six
classes (numbered 1 - 6)
• Each class is divided into subclasses
• Subclasses are divided into subsubclasses
• Subsubclasses are divided into individual
enzymes

11. Nomenclature
The name of the enzyme has two parts
The first part includes the name(s) of the
substrate(s) including substrate (coenzyme)
The second part includes the type of
reaction ending with -ase
If any additional information is to be given,
it is put in parenthesis at the end

14. You tube video link of this topic
• https://youtu.be/JZOx9v1V7mA
nomenclature of enzymes
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