Lesson17 Module 1

Glutamate decarboxylation results in the formation of inhibitory transmitter in CNS. Name it:

1. Glutathione

2. Gamma amino butyric acid*

3. Serotonin

4. Histamine

5. Asparagine

Which of the following statements related to biological role of transamination is wrong?

1. Redistribution of amino groups

2. Production of non-essential amino acids

3. Formation of biogenic amines*

4. Divergence the excess amino acids towards energy generation

5. Collection finally nitrogen in glutamate for subsequent deamination and urea synthesis

Point out the liver enzyme, which takes part in second step of transdeamination of amino acid:

A. Alpha-ketoglutarate dehydrogenase

B. Glutamate dehydrogenase*

C. Glutamate decarboxylase

D. L-Alanine oxidase

E. Tryptophan hydroxylase

Direct deamination is possible for two amino acids due to dehydratases (because of those amino acids side chain hydroxyl group is a good leaving group). Point out these amino acids:

1. Glutamate, aspartate

2. Serine, threonine*

3. Phenylalanine, tyrosine

4. Cysteine, methionine

5. Arginine, histidine

Human Glutamate dehydrogenase is predominantly located in the:

1. Cytosol

2. Inner mitochondrial membrane

3. Outer mitochondrial membrane

4. Mitochondrial matrix*

5. Endoplasmic reticulum

Choose the enzyme, whose genetic defect results in the GABA (Gamma-Amino Butyric Acid) levels decrease in the brain:

A. Tryptophan decarboxylase

B. Phenylalanine hydroxylase

C. Histidine decarboxylase

D. Alanine hydroxylase

E. Glutamate decarboxylase*

Which of the following coenzymes serves as a non-protein part of amino acid decarboxylase?

1. Pyridoxal phosphate*

2. Coenzyme A

3. Biotin

4. NADH

5. NADPH

The carbon skeletons of amino acids finally have one or more of the following fates except:

1. Oxidation via Krebs cycle to produce energy

2. Synthesis of glucose

3. Synthesis of urea*

4. Formation of fatty acid and ketone bodies

5. Synthesis of non-essential amino acids

The coenzyme that participates in transamination reaction is:

1. Coenzyme A

2. Coenzyme Q

3. Pyridoxal phosphate*

4. Thiamine pyrophosphate

5. NADPH

Norepinephrine is produced (in mammals) from:

1. Tryptophan

2. Tyrosine*

3. Pyruvate

4. Arginine

5. Tryptamine

The entry point into the citric acid cycle for isoleucine, valine, and the product of odd-chain fatty acids beta-oxidation is:

1. Pyruvate

2. Oxaloacetate

3. Citrate

4. Succinyl CoA*

5. Fumarate

The most important enzyme involved in oxidative deamination is:

1. L-amino acid oxidase

2. D-amino acid oxidase

3. Amino acid dehydrase

4. Histidase

5. Glutamate dehydrogenase*

Most amino acids undergo transamination to concentrate finally nitrogen in two amino acids, only, for subsequent urea formation. Choose these amino acids:

1. Lysine, proline

2. Glutamate, aspartate*

3. Alanine, phenylalanine

4. Serine, tyrosine

5. Arginine, histidine

Glutamate dehydrogenase is controlled by allosteric regulation. Point out the inhibitors of this enzyme:

1. ATP, GTP*

2. ADP, GDP

3. AMP, ADP

4. NAD⁺, NADP⁺

5. NADH, NADPH

Which of the following descriptions related to serotonin pathway isn’t correct?

1. Serotonin synthesis lowering in the brain causes depression

2. The largest amount of serotonin is synthesized in the intestinal cells*

3. The first enzyme of the pathway is tetrahydrobiopterin-dependent hydroxylase

4. The second enzyme of the pathway is biotin-dependent aromatic amino acid decarboxylase

5. Serotonin is synthesized from thyptophan

Name the ketogenic amino acids:

1. Leucine, lysine*

2. Alanine, arginine

3. Glutamate, aspartate

4. Cysteine, glycine

5. Arginine, asparagine

D-amino acid oxidase is important for the conversion of unnatural (for human body but regularly taken in the diet from plants) D—amino acids to L-amino acids. What prosthetic group is non-protein part of the enzyme?

1. NADH

2. NADPH

3. TPP

4. FAD*

5. Pyridoxal phosphate

Point out the enzyme, whose activity is determined in the blood plasma during the unicteric period of viral hepatitis:

A. Phenylalanine hydroxylase

B. Creatine phosphokinase

C. Glutamate dehydrogenase

D. Alanine transaminase*

E. Ornithine carbomoylphoshate transferase

Choose the enzyme of the blood plasma whose activity increases in ten or more times for 3-4 hours after myocardium infarction:

A. Alanine transaminase

B. Aspartate transaminase*

C. Alkaline phoshatase

D. Arginase

E. Leucine aminopeptidase

Point out the vitamin, whose deficiency causes the violations in the transamination and decarboxylation of amino acids:

A. Vitamin C

B. Vitamin B₁

C. Vitamin B₂

D. Vitamin B₉

E. Vitamin B_6*

Utilization of amino acids from the body pool is possible in all following ways except one. Choose it:

1. Porphyrins production

2. Purines production

3. Biogenic amine formation

4. Glucose and ketone bodies synthesis

5. Pyridoxal phosphate synthesis*

Point out the glucogenic amino acids:

A. Glutamate

B. Alanine

C. Serine

D. Aspartate

E. All the positions are right*

Point out the liver enzyme catalyzing the reversible oxidative deamination:

A. Glutamate dehydrogenase*

B. Alanine transaminase

C. Monoamino oxidase

D. Aspartate transaminase

E. Arginase

In course of histidine catabolism a biogenic amine is formed that has powerful vasodilatation effect. Name it:

1. Noradrenalin

2. Dioxyphenylalanine

3. Serotonin

4. Dopamine

5. Histamine*

According to clinical indications a patient was administered pyridoxal phosphate. What process is this medication intended to correct?

1. Deamination of purine nucleotide

2. Synthesis of purine and pyrimidine bases.

3. Transamination and decarboxylation of amino acids*

4. Protein synthesis

5. Oxidative decarboxylation of ketoacids

A patient diagnosed with carcinoma of bowels was admitted to the hospital. Analysis revealed high production of serotonin. It is known that this substance is formed from 5-hydroxy tryptophan amino acid. What biochemical mechanism underlies this process?

1. Formation of paired compounds

2. Decarboxylation*

3. Transamination

4. Microsomal oxidation

5. Desamination

The tested enzyme is related to the class of oxidoreductases and contains the coenzyme NADPH. It takes part in the oxidative deamination of one of the amino acids and in the reductive amination of alpha–ketoglutarate. Point out it:

A. Glutamate dehydrogenase*

B. Alanine transaminase

C. D-Alanine oxidase

D. Aspartate transaminase

E. Arginase

Immediate products of pyruvate metabolism (using one reaction only) are all except:

A. Acetyl-CoA

B. Alanine

C. Lactate

D. Oxaloacetate

E. 2-Phosphoglycerate*

An inhibitory mediator is formed by the decarboxylation of glutamate in the CNS. Name it:

1. Asparagine

2. Serotonine

3. Histamine

4. GABA *

5. Glutathione

It is known that the monoamine oxidase (MAO) enzyme plays an important part in the metabolism of catecholamine neurotransmitters. In what way this enzyme inactivates these neurotransmitters (norepinephrine, epinephrine, dopamine)?

1. Oxidative deamination *

2. Carboxylation

3. Addition of an amino group

4. Removal of a methyl group

5. Hydrolysis