NH

4

+

NH

4

+

Alanine

Glucose

Glucose

2-Oxoglutarate

2-Oxoglutarate

2-Oxoglutarate

Glutamate

Glutamate

Glutamate

Glutamine

H O

2

Carbamoyl-P

HCO

3

-

2ATP

ATP

2ADP

P

i

P

i

2-Oxoglutarate

Ornithine

Ornithine

Ornithine

Citrulline

Citrulline

Aspartate

Aspartate

AMP

PP

Argininosuccinate

Alanine

i

Fumarate

Oxaloacetate

Arginine

-OOCCH=CHCOO-

-OOCCH(OH)CH

2

COO-

-OOCCOCH

2

COO-

-

-

-

OOCCH CHCOO

2

(NH

)

3

+

DEAMINATION OF AMINO ACIDS - THE UREA CYCLE

Glutamate

Glutamate

Glutamine

OXIDATIVE

DEAMINATION

Gluconeogenesis

Catabolism etc.

Catabolism and/or

RCH

(NH

3

)

COO

-

+

RCH

(NH

3

)

COO

-

+

-

OOCCH

2

CH

2

CH

(NH

3

+)

COO

-

CH

3

CH

(NH

3

+)

COO

-

CH

3

CH

(NH

3

+)

COO

-

-

OOCCH

2

CH

2

CH

(NH

3

+)

COO

-

-

OOCCH2CH2CH

(NH

3

+)

COO

-

-

OOCCH2CH2CH

(NH

3

+)

COO

-

H

2

NOCCH

2

CH

2

CH

(NH

3

+)

COO

-

-

OOCCH2CH2COCOO

-

R.COCOO -

H3N[CH2]3CH(NH3+)COO-

H3N[CH2]3CH(NH3+)COO-

HN[CH2]3CH(NH

3

+

)COO-

Pyruvate

Pyruvate

-OOCCH CHCOO-

2

AMINO ACID I

AMINO ACID II

AMINO ACID I

AMINO ACID II

2-Oxo acid

2-Oxo acid

H2N

-

CO

-OP

H

2

N

-

C-

HN[CH2]3CH(NH

3

+

)COO-

HN[CH2]3CH(NH

3

+

)COO-

H

2

N=

C-

NH

H

2

N=

C-

NH

2

O

=

+

+

H

2

N-

CO-

NH

2

UREA

1.5 NADPH

NAD(P)H

1.5 NADP

+

NAD(P)

+

1.5O

2

NO

.

UREA CYCLE

REACTANTS PRODUCTS

MUSCLE

LIVER

UREA CYCLE

MITOCHONDRIAL INNER MEMBRANE

MITOCHONDRIAL INNER MEMBRANE

MITOCHONDRIAL MATRIX

NH

4

+

ADP+Pi

1.14.13.39

1.4.1.3

2.1.3.3

2.6.1.

2.6.1.

2.6.1.1.

2.6.1.2

2.6.1.2

3.5.1.2

3.5.3.10

4.3.2.1

6.3.1.2

6.3. 4.5

6.3.4.16

+ ATP

N-Acetylglutamate

GLYCOLYSIS

Urea

Glutamine

Glutamate

NH

4

+

NH

4

+

UREA CYCLE EQUATION

Aspartate

UREA

Fumarate

NH

4

+

+

HCO

3

-

+

-

OOC.CH

2

CH

(NH

3

+

)

COO

-

+ 3ATP

H

2

N

.

CO

.

NH

2

+

-

OOCCH=CHCOO

-

+ 2ADP + 2P

i

+ AMP +PP

i

AMINO ACIDS

GLUTAMATE

GLUTAMATE

GLUCOSE

ALANINE

CYCLE

LEUCINE, ISOLEUCINE, VALINE

MAINLY

AMINO ACIDS

3.5.3.10

Arginase

1.14.13.39 Nitric-oxide synthase

1.4.1.3

Glutamate dehydrogenase (NAD(P)

2.1.3.3

Ornithine carbamoyltransferase

2.6.1.-

Amino acid aminotransferase

2.6.1.1

Aspartate aminotransferase

ENZYMES

(ammonia)

6.3.4.16 Carbamoyl-phosphate synthase

1.1.1.37

Malate dehydrogenase

4.2.1.2

Fumarate hydratase

4.3.2.1

Argininosuccinate lyase

6.3.1.2

Glutamate-ammonia ligase

(Glutamine synthase)

6.3.4.5

Argininosuccinate synthase

3.5.1.2

Glutaminase

2.6.1.2

Alanine aminotransferase

Malate

Oxaloacetate

NAD

+

NADH+H

+

Gluconeogenesis

c 2001 IUBM B

U

R

E

A

C

Y

C

L

E

G

lu

con

eogen

es

is

H

2

O

2-Oxoglutarate

Glucose

SKELETAL & HEART MUSCLE, KIDNEY

Transport to Liver

3.5.1.2

1.4.1.3

CELL MEMBRANE

CELL MEMBRANE

CYTOSOL