amino acids
DESCRIPTION
N 2 NH 3 or NO 3 -. nitrogenase. soil bacteria. Plants & microorganisms. Amino acids. Plants require Nitrogen in the form of ammonia or nitrate. Animals require nitrogen in the form of amino acids. Both are dependent on soil bacteria to convert atmospheric nitrogen into useable forms. - PowerPoint PPT PresentationTRANSCRIPT
Amino acidsPlants & microorganisms
N2
NH3 or NO3-
soil bacterianitrogenase
Plants require Nitrogen in the form of ammonia or nitrate.Animals require nitrogen in the form of amino acids.
Both are dependent on soil bacteria to convert atmospheric nitrogen into useable forms.
Nitrogen-Fixing NodulesLegumes, e.g. soy beans can fix N2 –
Grains e.g. wheat/corn cannot – crop rotation
2 transamination ATP
3
catabolicOxidative deamination
Glucose
Fat
Protein translation
1anabolic
N - Cpds
Amino acidsPlants & microorganisms
N2
NH3 or NO3-
nitrogenase
RDI for protein 60g
Essential aa balance
-keto acids
COO-
|C=O |R
COO-
|C=O |CH3
Pyruvate
COO-
|C=O |CH2
|COO-
Oxaloacetate
-amino acids
COO-
|C-NH2
|R
COO-
|C-NH2
|CH3
Alanine COO-
|C-NH2
|CH2
|COO-
Aspartic Acid
Glucose
AcetylCoA
Pyruvate
NADH/FADH2
KrebsCycle
C6
C4
-ketoglutarate
C4oxaloacetate
Protein
Amino Acids
COO-
|C-NH2
|CH2
|CH2
|COO-
Glutamic acid
COO-
|C-NH2
|CH2
|COO-
Aspartic acid
Transamination
NH2
| +HOOC - CH - R
O ||HOOC - C - R
O || +HOOC - C - R
NH2
|HOOC - CH - R
Amino Transferasestransamination enzymes or transaminases
-ketoglutarate Glu and …Aspartate Aminotransferase Asp ↔ oxaloacetateAlanine Aminotransferase Ala ↔ pyruvateTyrosine Aminotransferase Tyr ↔ 4-hydroxyphenylpyruvateBranched Chain AA Aminotransferase (Leu, Ile, Val)Phosphoserine Aminotransferase
amino acid ‘X’ + -keto acid ‘Y’ ↔ amino acid ‘Y’ + -keto acid ‘X’
If the -keto acid corresponding to an amino acid is an intermediate of carbohydrate metabolism then that amino acid may be synthesized via a transamination reaction. Notable examples include Ala (pyruvate), Asp (oxaloacetate), and Glu (-keto-glutarate).
Alanine Aminotransferase Ala + -ketoglutarate ↔ pyruvate + Glu
NH2
| +HOOC - CH – CH3
O ||HOOC - C – CH2-CH2-COOH
O || +HOOC - C - CH3
NH2
|HOOC - CH - CH2-CH2-COOH
Oxidative Deamination
NH2
| HOOC - CH - CH2 - CH2 - COO-
+ NAD+ + H2O
O || HOOC - C - CH2 - CH2 - COO-
+ NADH + NH4+
Glutamate Dehydrogenase
Oxidative Deamination
(+ NAD+)
Amino Acid “X” + - Ketoglutarate
Transamination
Glutamate + - Keto Acid “X”
- Ketoglutarate + NH4+ + NADH
Glutamate Dehydrogenase
Glucose
AcetylCoA
Pyruvate
NADH/FADH2
KrebsCycle
C6
C4
-ketoglutarate
C4oxaloacetate
Protein
Amino Acids
OxidativeDeamination
Glucogenic Amino Acids
Glucogenic Amino Acids
Glucogenic Amino AcidsWill be deaminated via pyruvate or a Krebs intermediate & thus canbe converted into glucose.
Ketogenic Amino AcidWill be deaminated via AcetylCoAand thus can be made into a ketone body.
Glucose
AcetylCoA ↔ acetoacetylCoA
Pyruvate
NADH/FADH2
KrebsCycle
C6
C4
-ketoglutarate
C4oxaloacetate
LYSPHE→TYR
SuccinylCoA
fumarate
Glucogenic/Ketogenic/both
LEUTRP
ILE
ARGGLUGLNHISPRO
ALACYSGLYSERTHRTRP
ASN
ASP
PHETYR
ILEMETTHRVAL
NH3+
|- CH2 - CH - COO-
PHE
CH2 - COO-
HO - - OH
Homogentisate
NH3+
|- CH2 - CH - COO-HO -
TYR
Phe Hydroxylase
O ||- CH2 - C - COO-HO -
Tyraminotransferase
CH2 - COO-
HO - - OH Homogentisate
-OOC - CH = CH - C - CH2 - C - CH2 - COO-
|| || O O
cis
-OOC - CH = CH - C - CH2 - C - CH2 - COO-
|| || O O
trans
H ||-OOC - C = C - COO- + H3C - C - CH2 - COO-
H
O acetoacetatefumarate
Phenylalanine Hydroxylase & PKU
Phe + tetrahydrobiopterin Tyr + H2O + dihydrobiopterin
[Phe] = 0.1 mM normally 1.2 mM in PKU
1 in 20,000 homozygous1 in 150 heterozygous
IQ study: 53 93
Glucose
AcetylCoA ↔ acetoacetylCoA
Pyruvate
NADH/FADH2
KrebsCycle
C6
C4
-ketoglutarate
C4oxaloacetate
PHE phenylalanine hydroxylase
TYR
Bridging Reaction
SuccinylCoA
fumarate
PKU Xphenylpyruvate
PKU X
O O || || H3N+- CH - C - N - CH - C - O-CH3
| | CH2 CH2
| | COO-
Asp Phe
aspartame
H
Glucose
AcetylCoA
Pyruvate
NADH/FADH2
KrebsCycle
C6
C4
C5
C4
ATP
ADP O2
NAD+/FAD
oxaloacetate
Protein
Amino Acids
Ubiquitin Protein digestion (t1/2)
Ubiquitin is a protein ‘tag’ that marks another protein for proteolytic destruction
UbiquitinUbiquitin activating enzyme (E1): ubiquitin + ATP ubiquitin-AMP + PPi
Ubiquitin-conjugating enzyme (E2): attaches to activated ubiquitin via SH
Ubiquitin-protein ligase (E3): transfers ubiquitin to e-amino of target protein t1/2 & N-terminal rule (e.g. R = 2 min. M = 20 hrs.)
Proteosome: (a 26s protease complex) digests ubiquitin-tagged proteins
Slow (>20 hr.) : Ala, Cys, Gly, Met, Pro, Ser, Thr, Val
Fast (2-20 min.) : Arg, Asx, Glx, His, Ile, Leu, Lys, Phe, Trp, Tyr
Processes regulated by protein destruction gene transcription circadian rhythms inflammatory response antigen processesing tumor supression
Ubiquitin activating enzyme (E1): ubiquitin + ATP ubiquitin-AMP + PPi
Ubiquitin-conjugating enzyme (E2): attaches to activated ubiquitin via SH
Ubiquitin-protein ligase (E3): transfers ubiquitin to e-amino of target protein t1/2 & N-terminal rule (e.g. R = 2 min. M = 20 hrs.)
Urea Cycle
NH4+ + CO2 + 3ATP + Asp + 2 H2O
urea + 2ADP, Pi + AMP, PPi + fumarate
||H2N – C – NH2
O
Detoxification of ammonia