Food Biochemistry and Food Processing

190 Part II: Water, Enzymology, Biotechnology, and Protein Cross-linking

Table 8.3.The Characteristic of Each Type of Inhibition and Their Effect on the Kinetic

Parameters Kmand Vmax

Inhibitor Type Binding Site on Enzyme Kinetic Effect

Competitive The inhibitor specifically binds

inhibitor at the enzyme’s catalytic site,

where it competes with substrate

for binding:

EI

Kmis increased, Vmaxis unchanged.

LB equation:

Noncompetitive The inhibitor binds to E or

inhibitor to the ES complex (may form

an EIS complex) at a site other

than the catalytic. Substrate

binding is unchanged, whereas

EIS complex cannot form

products:

Kmis unchanged, Vmaxis decreased

proportionately to inhibitor concentration.

LB equation:

Uncompetitive Binds only to ES complexes at
inhibitor a site other than the catalytic site.
Substrate binding alters enzyme
structure, making inhibitor-
binding site available:

EIS

Kmand Vmaxare decreased.

LB equation:

111

1

v

K

VSV

I

K

m

i

=⋅+ +

⎛

⎝⎜

⎞

max [] max ⎠⎟

[]

E ES E + P

+S

-S

←⎯⎯⎯→⎯ →

1

1

11

1

v

K

V

I

KSV

I

K

m

ii

=⋅+

⎛

⎝⎜

⎞

⎠⎟

⋅+ +

⎛

max max⎝

[]

[]

[]

⎜⎜

⎞

⎠⎟

EI EIS

+S

-S

←⎯⎯⎯→⎯

E ES E + P

+S

-S

←⎯⎯⎯→⎯ →

1

1

11

v

K

V

I

KSV

m

i

=⋅+

⎛

⎝⎜

⎞

⎠⎟

⋅+

max max

[}

[]

E ES E + P

+S

-S

←⎯⎯⎯→⎯ →

I (^2)
I
I (^2)
I I (^2)
I
I (^2)
I