Chapter 26, Problem 26.103EP

(a)

Interpretation Introduction

Interpretation: To identify whether citrulline is encountered in the (1) urea cycle, (2) heme degradation process, or (3) oxidative deamination reaction.

Concept introduction: A urea cycle is a cyclic biochemical pathway that involves the production of urea using ammonium ions and aspartate molecules as nitrogen sources. The desired product of the urea cycle is urea.

Heme potion of hemoglobin undergoes a stepwise degradation to biliverdin, to bilirubin, and then to bile pigments that are excreted from the body.

A biochemical reaction in which an $\text{α-amino}$ acid is converted into $\text{α-keto}$ acid along with the release of an ammonium ion is known as oxidative deamination reaction. A general oxidative deamination reaction is as follows:

$\text{α-amino acid}+{\text{NAD}}^{+}+{\text{H}}_{\text{2}}\text{O}\to \text{α-keto acid}+{\text{NH}}_4^{+}+\text{NADH}+{\text{H}}^{+}$

(b)

Interpretation Introduction

Interpretation: To identify whether glutamate is encountered in the (1) urea cycle, (2) heme degradation process, or (3) oxidative deamination reaction.

Concept introduction: A urea cycle is a cyclic biochemical pathway that involves the production of urea using ammonium ions and aspartate molecules as nitrogen sources. The desired product of the urea cycle is urea.

Heme potion of hemoglobin undergoes a stepwise degradation to biliverdin, to bilirubin, and then to bile pigments that are excreted from the body.

A biochemical reaction in which an $\text{α-amino}$ acid is converted into $\text{α-keto}$ acid along with the release of an ammonium ion is known as oxidative deamination reaction. A general oxidative deamination reaction is as follows:

$\text{α-amino acid}+{\text{NAD}}^{+}+{\text{H}}_{\text{2}}\text{O}\to \text{α-keto acid}+{\text{NH}}_4^{+}+\text{NADH}+{\text{H}}^{+}$

(c)

Interpretation Introduction

Interpretation: To identify whether bilirubin is encountered in the (1) urea cycle, (2) heme degradation process, or (3) oxidative deamination reaction.

Concept introduction: A urea cycle is a cyclic biochemical pathway that involves the production of urea using ammonium ions and aspartate molecules as nitrogen sources. The desired product of the urea cycle is urea.

Heme potion of hemoglobin undergoes a stepwise degradation to biliverdin, to bilirubin, and then to bile pigments that are excreted from the body.

A biochemical reaction in which an $\text{α-amino}$ acid is converted into $\text{α-keto}$ acid along with the release of an ammonium ion is known as oxidative deamination reaction. A general oxidative deamination reaction is as follows:

$\text{α-amino acid}+{\text{NAD}}^{+}+{\text{H}}_{\text{2}}\text{O}\to \text{α-keto acid}+{\text{NH}}_4^{+}+\text{NADH}+{\text{H}}^{+}$

(d)

Interpretation Introduction

Interpretation: To identify whether ammonium ion is encountered in the (1) urea cycle, (2) heme degradation process, or (3) oxidative deamination reaction.

Concept introduction: A urea cycle is a cyclic biochemical pathway that involves the production of urea using ammonium ions and aspartate molecules as nitrogen sources. The desired product of the urea cycle is urea.

Heme potion of hemoglobin undergoes a stepwise degradation to biliverdin, to bilirubin, and then to bile pigments that are excreted from the body.

A biochemical reaction in which an $\text{α-amino}$ acid is converted into $\text{α-keto}$ acid along with the release of an ammonium ion is known as oxidative deamination reaction. A general oxidative deamination reaction is as follows:

$\text{α-amino acid}+{\text{NAD}}^{+}+{\text{H}}_{\text{2}}\text{O}\to \text{α-keto acid}+{\text{NH}}_4^{+}+\text{NADH}+{\text{H}}^{+}$