Test Mtb Amino Acids

8/3/2019 Test Mtb Amino Acids

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Metabolism of amino acids- exercise -

Vladimíra Kvasnicová



Choose essential amino acids

a) Asp, Glu

b) Val, Leu, Ile

c) Ala, Ser, Gly

d) Phe, Trp



Essential amino acids

1) branched chain: Val, Leu, Ile

2) basic: His, Arg, Lys

3) aromatic: Phe ( → Tyr), Trp

4) sulfur-containing: Met ( → Cys)

5) other: Thr

„10“



Choose amino acids from which the

other amino acid can be synthesized ina human body

a) valine → leucine

b) aspartate → asparagine

c) phenylalanine → tyrosine

d) methionine + serine → cysteine



Choose amino acids from which the

other amino acid can be synthesized ina human body

a) valine → leucine leucine is the essential AA

b) aspartate → asparagine

c) phenylalanine → tyrosine

d) methionine + serine → cysteine



Synthesis of

ASPARAGINE

needs glutamine as–NH

2group donor

(it is not ammonia as in the Gln synthesis)

The figure was adopted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed.Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2



The figure is from http://web.indstate.edu/thcme/mwking/amino-acid-metabolism.html (Jan 2007)

Synthesis of Tyr from Phe




Synthesis of Cys from Met and Ser



The amino acids can be formed from thecitrate cycle intermediates

in a human body

a) αααα-ketoglutarate → glutamate

b) succinyl-CoA → isoleucine

c) oxaloacetate → aspartate

d) malate → threonine



The amino acids can be formed from

the citrate cycle intermediatesin a human body

a) αααα-ketoglutarate → glutamate

b) succinyl-CoA → isoleucine Ile is the essential AA

c) oxaloacetate → aspartate

d) malate → threonine Thr is the essential AA



The figure is from http://www.tcd.ie/Biochemistry/IUBMB-Nicholson/gif/13.html (Dec 2006)

Amphibolic

characterof citrate cycle



The compound(s) can be synthesizedfrom the amino acid

a) tyrosine → serotonin

b) serine → ethanolamine

c) tryptophan → catecholamines

d) cysteine → taurine



The compound(s) can be synthesizedfrom the amino acid

a) tyrosine → serotonin Tyr → catecholamines

b) serine → ethanolamine formed by decarboxylation

c) tryptophan → catecholamines Trp → serotonin

d) cysteine → taurine




taurin is used in conjugation reactions in the liver– it is bound to hydrophobic substances to increase their solubility

(e.g. conjugation of bile acids)



If the amino acid is metabolised the

substance is formed:

a) methionine gives homocysteine

b) serine gives glycine and folic acidderivative: methylene tetrahydrofolate

c) glutamine releases ammonia

d) some amino acides can be degraded toacetoacetate



If the amino acid is metabolised the

substance is formed:

a) methionine gives homocysteine

b) serine gives glycine and folic acidderivative: methylene tetrahydrofolate

c) glutamine releases ammonia

d) some amino acides can be degraded toacetoacetate = one of ketone bodies




B12

Regeneration of

Met(vitamins: folate+B

12)



The figure is from http://www.biocarta.com/pathfiles/GlycinePathway.asp (Jan 2007)

Synthesis of serine and glycineglycolysis



Choose products of the transamination

reactions

a) alanine → pyruvate

b) glutamate → 2-oxoglutarate

c) aspartate → oxaloacetate

d) phenylalanine → tyrosine



Choose products of the transamination

reactions

a) alanine → pyruvate

b) glutamate → 2-oxoglutarate

c) aspartate → oxaloacetate

d) phenylalanine → tyrosine it is not transamination



The figure is from http://web.indstate.edu/thcme/mwking/nitrogen-metabolism.html (Jan 2007)

Transamination reaction! REVERSIBLE !

enzymes: amino transferases

coenzyme: pyridoxal phosphate (vit. B6 derivative)




alanine aminotransferase(ALT = GPT)

aspartate aminotransferase(AST = GOT)

Amino transferases important in medicine

(„transaminases“)



Amino nitrogen released from carbon

skeletons of AAs can be transported inblood as

a) NH4+

b) alanine

c) glutamine

d) urea



Amino nitrogen released from carbon

skeletons of AAs can be transported inblood as

a) NH4+ physiologically up to 35 mol/l (NH

3+ H +

↔ NH4+)

b) alanine formed by transamination from pyruvate

c) glutamine the most important transport form of –NH 2

d) urea it is the end product of degradation of amino nitrogen (liver → kidneys → urine)



Transport ofamino nitrogen

from degraded muscle proteins

products excreted with urine

The figure was adopted from Devlin, T. M. (editor): Textbook

of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss,Inc., New York, 1997. ISBN 0-471-15451-2



Glucose-alanine cycle


alanine transfersboth the carbon

skeleton forgluconeogenesisand –NH

2group



glutamine synthetase

GLUTAMINE

= the most important transport form af amino

nitrogen in blood

it transfers two amino groups released by degradation of AAs




Choose glucogenic amino acids

a) alanine

b) lysine

c) leucine

d) glutamine



7 degradation products of AAs

1. pyruvate ←←←← Gly, Ala, Ser, Thr, Cys, Trp

2. oxaloacetate ←←←← Asp, Asn

3. αααα-ketoglutarate ←←←← Glu, Gln, Pro, Arg, His

4. succinyl-CoA ←←←← Val, Ile, Met, Thr

5. fumarate ←←←← Phe, Tyr

6. acetyl-CoA ←←←← Ile

7. acetoacetyl-CoA ←←←← Lys, Leu, Phe, Tyr, Trp

glucogenic AAs

ketogenic AAs



Glutamate dehydrogenase (GMD)

a) catalyzes conversion of Glu to oxaloacetate

b) is found in mitochondria of hepatocytes

c) produces ammonia

d) needs pyridoxal phosphate as a coenzyme



The figure is from http://web.indstate.edu/thcme/mwking/nitrogen-metabolism.html (Jan 2007)

GLUTAMATE DEHYDROGENASE

removes amino group from carbon sceleton of Glu in the liver

1. –NH2 from AAs was transfered by transamination→ Glu2. free ammonia is released by oxidative deamination of Glu



Choose correct statement(s) about

metabolism of amino acids

a) alanine aminotransferase (ALT) transforms

pyruvate to alanine

b) aspartate aminotransferase (AST) transforms

aspartate to αααα-ketoglutarate

c) glutamine synthetase transforms glutamate to

glutamined) glutaminase catylyzes conversion of glutamine

to ammonia and αααα-ketoglutarate



Choose correct statement(s) about

metabolism of amino acids

a) alanine aminotransferase (ALT) transforms

pyruvate to alanine

b) aspartate aminotransferase (AST)

transforms aspartate to αααα-ketoglutarate

c) glutamine synthetase transforms glutamateto glutamine

d) glutaminase catylyzes conversion ofglutamine to ammonia and αααα-ketoglutarate

A i f i i di i




alanine aminotransferase(ALT = GPT)

aspartate aminotransferase(AST = GOT)

Amino transferases important in medicine(„transaminases“)

Glutamine is principal



Glutamine is principaltransport form of amino nitrogen

The figure is from http://www.sbuniv.edu/~ggray/CHE3364/b1c25out.html (Dec 2006)



The amino acids can enter the citrate

cycle as the molecules

a) alanine →→ acetyl-CoA

b) aspartate → oxaloacetate

c) valine →→ succinyl-CoA

d) glutamine →→ αααα-ketoglutarate



The amino acids can enter the citrate

cycle as the molecules

a) alanine →→ acetyl-CoA

b) aspartate → oxaloacetate

c) valine →→ succinyl-CoA

d) glutamine →→ αααα-ketoglutarate

Th t f i id i t th it t l



The figure is from http://www.biocarta.com/pathfiles/glucogenicPathway.asp (Jan 2007)

The entrance of amino acids into the citrate cycle



Ornithine cycle

a) proceeds only in the liver

b) produces uric acid

c) includes arginine as an intermediate

d) produces energy in a form of ATP



Ornithine cycle

a) proceeds only in the liver

b) produces uric acid

c) includes arginine as an intermediate

d) produces energy in a form of ATP

D f h l



The figure is from http://www.biocarta.com/pathfiles/ureacyclePathway.asp (Jan 2007)

Detoxication of ammonia in the liver

Interconnection of the urea cycle with the



The figure is from http://courses.cm.utexas.edu/archive/Spring2002/CH339K/Robertus/overheads-3/ch18_TCA-Urea_link.jpg

(Jan 2007)

Interconnection of the urea cycle with thecitrate cycle



In the urea synthesis

a) ammonia reacts with ornithine → citrulline

b) carbamoyl phosphate synthetase I (=mitochondrial) regulates the cycle

c) aspartate is used as a –NH2 group donor

d) urea is formed – it can be used as an energysubstrate for extrahepatic tissues



• arginineN-acetylglutamate

synthetase

• N-acetylglutamatecarbamoyl phosphatesynthetase I(= mitochondrial)

inhibition activation regulatory enzyme

Regulation of urea cycle

allosteric regulation + enzyme induction by protein rich diet or by metabolic changes during starvation

Urea synthesis is inhibited by acidosis

– HCO 3 -

is saved

Test Mtb Amino Acids

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