Enzymology Class
Topic 1: Introduction
(A) Historical Perspectives
(B) Enzyme as Biological Catalysts
(C) Theory of Enzyme Action
(D) Active Site of Enzyme
Enzymology Slides
(E) Co-factors and Co-enzymes
(F) Classification of Enzymes
1 2
Enzymology Slides Enzymology Slides
Historical Perspectives Enzyme as Biological Catalysts
Enzymology and biochemistry evolved from the 19th century
Early history of enzyme involved practical applications of
Investigation on the nature of animal digestion and fermentation:
enzyme activities in daily life:
• Pepsin was discovered as the active principle in the acid
• The leavening of bread by yeast, which results from
extract of gastric mucosa causing the dissolution of
the enzymatic production of carbon dioxide
coagulated egg white (1834)
• Miso soup and soy sauce production
• Other “soluble ferments” discovered in the 19th century
(using enzymes from grown microorganisms)
include trypsin (1857), invertin (later invertase and
• Apple cider vinegar production
sucrase, 1864), papain (“vegetable trypsin”, 1879), etc.
• Use of papaya fruit juice as meat tenderizer
• Enzymes for alcoholic fermentation were found to be
• Beer and wine production
active in cell free extracts of yeast
• Cheese production
• Yogurt, sour milk
preparation
3 4
Enzymology Slides Enzymology Slides
, Enzyme as Biological Catalysts
• Relationship of initial velocity (V0) and substrate
concentration (S) was examined
• A mathematical description was established for the
kinetics of enzyme action (Michaelis and Menten,
1913)
• Weak-bonding interactions between the enzymes
and their substrates were proposed to distort the
substrate and catalyze a reaction (Haldane, 1930s)
Leonor Michaelis Maud Menten John Burdon Haldane
5 (1875-1949) (1879-1960) (1892-1964) 6
Enzymology Slides
Enzyme as Biological Catalysts Enzyme as Biological Catalysts
What is Enzyme?
Enzymes were found to be proteins
Urease crystals (X 728)
• The question of homogeneity of the enzyme
Sumner, J. B. (1926) “ The
preparations frustrated the field of Enzymology for isolation and crystallization of
many decades. the enzyme urease” J. Biol.
Chem. 69:435-441.
• Filterable coenzymes (co-ferments) were discovered
in Buchner’s zymase (Harden and Young, 1906).
• Enzymes were thought to be small reactive
molecules adsorbed on inactive colloidal material,
including proteins ( as by R. Willstätter in the 1920s).
• Urease (1926, Sumner) and pepsin (1930, Northrop)
were crystallized and found to be solely made of
proteins.
7 8
Enzymology Slides Enzymology Slides
Topic 1: Introduction
(A) Historical Perspectives
(B) Enzyme as Biological Catalysts
(C) Theory of Enzyme Action
(D) Active Site of Enzyme
Enzymology Slides
(E) Co-factors and Co-enzymes
(F) Classification of Enzymes
1 2
Enzymology Slides Enzymology Slides
Historical Perspectives Enzyme as Biological Catalysts
Enzymology and biochemistry evolved from the 19th century
Early history of enzyme involved practical applications of
Investigation on the nature of animal digestion and fermentation:
enzyme activities in daily life:
• Pepsin was discovered as the active principle in the acid
• The leavening of bread by yeast, which results from
extract of gastric mucosa causing the dissolution of
the enzymatic production of carbon dioxide
coagulated egg white (1834)
• Miso soup and soy sauce production
• Other “soluble ferments” discovered in the 19th century
(using enzymes from grown microorganisms)
include trypsin (1857), invertin (later invertase and
• Apple cider vinegar production
sucrase, 1864), papain (“vegetable trypsin”, 1879), etc.
• Use of papaya fruit juice as meat tenderizer
• Enzymes for alcoholic fermentation were found to be
• Beer and wine production
active in cell free extracts of yeast
• Cheese production
• Yogurt, sour milk
preparation
3 4
Enzymology Slides Enzymology Slides
, Enzyme as Biological Catalysts
• Relationship of initial velocity (V0) and substrate
concentration (S) was examined
• A mathematical description was established for the
kinetics of enzyme action (Michaelis and Menten,
1913)
• Weak-bonding interactions between the enzymes
and their substrates were proposed to distort the
substrate and catalyze a reaction (Haldane, 1930s)
Leonor Michaelis Maud Menten John Burdon Haldane
5 (1875-1949) (1879-1960) (1892-1964) 6
Enzymology Slides
Enzyme as Biological Catalysts Enzyme as Biological Catalysts
What is Enzyme?
Enzymes were found to be proteins
Urease crystals (X 728)
• The question of homogeneity of the enzyme
Sumner, J. B. (1926) “ The
preparations frustrated the field of Enzymology for isolation and crystallization of
many decades. the enzyme urease” J. Biol.
Chem. 69:435-441.
• Filterable coenzymes (co-ferments) were discovered
in Buchner’s zymase (Harden and Young, 1906).
• Enzymes were thought to be small reactive
molecules adsorbed on inactive colloidal material,
including proteins ( as by R. Willstätter in the 1920s).
• Urease (1926, Sumner) and pepsin (1930, Northrop)
were crystallized and found to be solely made of
proteins.
7 8
Enzymology Slides Enzymology Slides
