Enzymes, its properties,enzyme specificity,history,nomenclature,coding and naming

1. ENZYMES
By- Sanjesh Kumar

2. Introduction
The word enzyme is made up of two greek words –’En’- means inside and ‘zyme’ means yeast i.e the word
enzyme means inside yeast.
DEFINATION
Enzymes can be defined as the proteins (Bio-molecules)
that act as catalyst in a particular reaction i.e increases
therateof thereaction.
CATALYST
Catalyst are the substances that speed up a particular
reaction without being consumedin a reaction.
DEPICTION
Catalyst=Enzymes

3. History
•In 1850s Louis Pasteur postulated for the first time that fermentation
of sugar into alcohol was catalysed out by ferments.
• this was the basis of his hypothesis called vitalism.
•acc. to which ferments were responsible for the catalytic reaction.
Date
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4. Yeast extract
1897 Buchner proved that yeast extracts, not live yeast could
ferment sugar.
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5. term designation
The term Enzyme was coined by -
Fredrick W. Kuhne
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6. Chemical nature
The 1st isolated enzyme was urease by james Sumner 1926 – he
proved enzymes were protein.
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7. Properties Of enzymes
Bond
They are high molecular weight
compounds made up principally of
chains of amino acids linked together by
peptide bonds.
Protein nature
All known enzymes are
proteins(Except RNAs)

8. Properties Of enzymes
•Enzymes can be denatured and precipitated with salts, solvents and other reagents.
•Many enzymes require the presence of other compounds.This entire active complex is referred to as the holoenzyme;
i.e.apoenzyme (protein portion) plus the cofactor (coenzyme, prosthetic group or metal-ionactivator) the whole combination is
called the holoenzyme.
•Apoenzyme + Cofactor = Holoenzyme

9. Properties Of enzymes
According to Holum, the cofactor may be:
• A coenzyme- a non-protein organic substance which is thermostable and loosely attached to the protein part.
• A prostheticgroup- an organic substance which is dialyzable and thermostable which is firmly attached to the
protein or apoenzyme portion.
• A metalion-activator- these include K+, Fe++, Fe+++, Cu++, Co++, Zn++, Mn++, Mg++, Ca++and Mo+++.

10. Active site
enzyme’s
catalytic site;
substrate fits
into active site
Terminology
Substrate
reactant
which binds
to enzyme
Enzyme-
substrate
complex:=te
mporary
association
Product
end result of
reaction
active site

11. Enzyme Specificity
A few enzymes exhibit absolute specificity; that is, they will catalyze only one particular reaction. Other enzymes will be specific for a
particular type of chemical bond or functional group. In
general, there are four distinct types of specificity:
Groupspecificity
the enzyme will act only on
molecules that have specific
functional groups, such as
amino, phosphate and methyl
groups.
Stereochemicalspecificity
the enzyme will act on a
particular steric or optical
isomer.
Absolute specificity -
the enzyme will catalyze only
one reaction.
Linkagespecificity
the enzyme will act on a
particular type of chemical
bond regardless of
the rest of the molecular
structure.

12. Nomenclature
There are many methods for naming enzymes:
• The old trivial name as pepsin and trypsin.
•The name of substrate and the suffix – ase added to it as lactase
acting on lactose and sucrase acting on sucrose.
Two words, one for the substrate and the other for the type of
reaction e.g. succinate dehydrogenase, pyruvate decarboxylase
and glutamine synthetase.

13. Enzyme coding
Each enzyme has a numerical code which is formed of four digits separated by
dots:
•The first digit denotes the class (reaction type) of the enzyme.
• The second digit denotes the functional group upon which the enzyme acts.
•The third digit denotes the coenzyme.
•The fourth digit denotes the substrate.
For example 1.1.1.1 enzyme, 1 means oxidoreductase, 1.1 means that the functional
group is hydroxyl group (-OH), 1.1.1 means NAD is the coenzyme and 1.1.1.1 means
alcohol. So, 1.1.1.1 means alcohol dehydrogenase enzyme.

14. Any questions
Drop question in comment box
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15. Thank You!
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