Enzymes in Functional Group Transformation: Oxygenases and Peroxidases, Slides of Biochemistry

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Module 9: Enzymes in Functional

G

T

f

ti

Group TransformationLecture19: Enzymes in

Functional Group

Transformation

Oxygenation reactionsOxygenation

reactions

Oxygen transfer from molecular oxygen into organic acceptor molecules

may proceed through three different mechanisms.

Mono-oxygenases incorporate one oxygen from molecular oxygen into the

substrate, the other is reduced at the expense of a donor (UsuallyNADH or NADPH) to form water.

Di-oxygenases simultaneously incorporate both oxygen atoms of O2 into

the substrate by forming a peroxy-species, thus they are sometimesmisleadingly called oxygen-transferases.

Oxidases, on the other hand, mainly catalyze the electron-transfer onto

molecular oxygen. This may proceed through a two or four electrontransfer, involving either H

O 2

2

or water as oxygen donor

Some example of monooxygenase catalyzed biotransformations

O

2

O

O

Monooxygenases

X

OR

O

O

OH

H

X-O

OH

O

Docsity.com

Sub

• e

Sub

S b

H O

Catalytic cycle of cytochrome P-450 dependent monooxygenases

Fe

3+ S

N N

N N

O

H

H

Fe

3+ S

N N

N N^

Fe

2+ S

N N

N N

• e

Sub

H

O 2

O

2

H

SubO O^2

Fe

3+ N

N

O

O

3+ N

N

O

O

Fe

5+ N

N

O

Sub

• e

Sub

Sub

2

Fe S N

N

Fe S N

N

Fe S N

N

2H

H

O 2

N

N

Sub O4+Fe^ S N N

N N

O

H

Asymmetric microbial hydroxylation by monooxygenase of iso-butyric acid

CO

H 2

CO

H 2

microorganismO

2

S

CO

H 2

O

H

R

Microorganism

Configuration

ee (%)

P. putida

ATCC 21244

S^

Candida rugosa

NBRC

S

g

Candida rugosa

NBRC 1542

R

P

seudomonas putida

Oxidoreductase mediated synthesis of captopril

OH

O

OH

O

H

p

(ATCC 21244)

SOCl

, L-Proline, NaOH 2

O

S -

β-hydroxyisobutyric acid

Cl

O

CO

H 2

S

H

O

CO

H 2

NaSH

Captopril (ACE inhibitor)

Bioconversion of limonene using various biocatalysts

O

H

OH

CHO

Mentha spicata

Perilla futescens

Mentha piperita

(-)-limonene

(-)-perilyl alcohol

(-)-perilyl aldehyde

trans-carveol

O

OH

O

(-)-carvone

trans-isopiperitenol

(-)-menthone

The use of substrate engineering in bihydroxylation

introduction ofd/

The

use of substrate engineering in bihydroxylation

R

R

X

A

d/p group

B

Direct hydrioxylationdifficult to obtain

biohydroxylation

d/

l

R

OH

R

X

OH

D

C

d/p gr removal

1. The d/p (docking/protecting )group is introduced into the substrate2. The new substrate is then more easily converted in the biohydroxylation reaction.3. The d/p group is finally removed to produce hydroxylated final product.