A i A id M t b liA i A id M t b liAmino Acids MetabolismAmino Acids Metabolism
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
١
T iT iT iT i•• TyrosineTyrosine•• TyrosineTyrosine
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٢
TyrosineTyrosine NH2TyrosineTyrosineCH2 CH COOH
NH2
• It is α-amino, β-hydroxphenyl propionicStructureStructure
OHIt is α amino, β hydroxphenyl propionic
Nutrional ValueNutrional ValueOH
• It is nonnon--essentialessential amino acid
Metabolic FateMetabolic Fate• It is bothboth glucogenic and ketogenicMetabolic FateMetabolic Fate
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٣
TyrosineTyrosine
BiosynthesisBiosynthesis1. From phenylalanine
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٤
TyrosineTyrosine
1 Incorporated in protein structure
Metabolic FateMetabolic Fate1. Incorporated in protein structure2. Phosphoproteins 3 Biosynthesis of thyroid hormones3. Biosynthesis of thyroid hormones4. Biosynthesis of catecholamines5 Bi s th sis f l i i t 5. Biosynthesis of melanin pigment 6. Catabolised to fumarate and acetoacetate7 S th i f l7. Synthesis of glucose8. Synthesis of ketone bodies9 P t f ti9. Putrefaction
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٥
TyrosineTyrosineBiosynthesis of thyroid hormonesBiosynthesis of thyroid hormonesBiosynthesis of thyroid hormonesBiosynthesis of thyroid hormones
NH2CH CH COOH
NH2CH CH COOH
NH2
CH2 CH COOH CH2 CH COOH CH2 CH COOH
OH OHI
OHI I
II
Tyrosine Monoiodotyrosine Diiodotyrosine
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٦
TyrosineTyrosineBiosynthesis of thyroid hormonesBiosynthesis of thyroid hormones CH2 CH COOH
NH2
Biosynthesis of thyroid hormonesBiosynthesis of thyroid hormones
CH2 CH COOHNH2
CH2 CH COOHNH2
2
OI I
d l2
I OHI I
O
INH2
+Oxidative coupling
OHI OH
OHI
NH2
CH3 CH COOH
Monoiodotyrosine Diiodotyrosine Triiodothyronine (T3)Alanine
CH2 CH COOHNH2
CH2 CH COOHNH2
CH2 CH COOHNH2
Oxidative coupling
OI I
OHI I
OHI I
CH3 CH COOHNH2
+Oxidative coupling
OHI I
CH3 CH COOH
Diiodotyrosine Diiodotyrosine
Tetraiodothyronine (T4)Alanine
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٧
TyrosineTyrosineBiosynthesis of catecholaminesBiosynthesis of catecholaminesBiosynthesis of catecholaminesBiosynthesis of catecholamines
CH2 CH COOHNH2
CH2 CH COOHNH2 CH2 CH2 NH2
DOPA DOPA TyrosineTyrosine
OH OHHO
OHHO
DecarboxylaseDecarboxylaseTyrosineTyrosine
hydroxylasehydroxylase PLPCO2OH
TyrosineDihydroxy phenylalanine
DOPADopamineDopamine
CO2
Dopamine Dopamine ββ hydroxylasehydroxylase
½ O2
OHOH
Vit Cββ hydroxylasehydroxylase
CH CH2 NH2CH CH2 NH CH3
OHHO
OHHO NoradrenalineNoradrenaline
AdrenalineAdrenaline CH3
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٨
TyrosineTyrosineBiosynthesis of melanin pigmentBiosynthesis of melanin pigmentBiosynthesis of melanin pigmentBiosynthesis of melanin pigment
CH2 CH COOHNH2
CH2 CH COOHNH2
CH CH COOHNH2
CH2 CH COOH CH2 CH COOH
HO
CH2 CH COOH
O
Tyrosine Tyrosine hydroxylasehydroxylase
TyrosinaseTyrosinase
OH OH OO
T i
Dihydroxy phenylalanineDOPA
Dopaquinone
Tyrosine DOPA
DopachromeDopachrome
Melanin pigment
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
٩
TyrosineTyrosineNH2
PutrefactionPutrefaction CH2 CH2 COOHCH2 CH COOH
2
P hydroxyphenyl
OHOH
P hydroxyphenylpropionicDecarboxylationDecarboxylation
CH2 COOHCH2 CH2 NH2
Tyrosine
P hydroxyphenyl
OHOH
yd o yp e yacetic
CH3 NH2
CH3
Tyramine
OHOH
P cresolPhenolPhenol
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
١٠
OH
TyrosineTyrosineTyrosine catabolismTyrosine catabolismTyrosine catabolismTyrosine catabolism
CH2 CH COOHNH2 OH
CH2 COOH
Homogentisic acidCH2 C COOH
O
TransaminaseTransaminase HydroxylaseHydroxylase
OHOH
OH
P hydroxyphenyl pyruvicHomogentisic oxidaseHomogentisic oxidase
α KG Glu ½ O2 CO2
VitC½ O2
PLP
CCOOHHC CH2 COOH
O
P hydroxyphenyl pyruvicMalyl acetoacetateTyrosine
CH2
HC
HCCO
II
CHOOC CH CH2 COOHO
O
IsomeraseIsomeraseFumaryl acetoacetateFumaryl acetoacetate
hydrolasehydrolaseCH2HC
CO
CH3 C CH2 COOH CHCH COOH
HOOC
Fumaryl acetoacetateAcetoacetate Fumarate
+H2O
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
١١
Fumaryl acetoacetate
Tyrosine MatabolismTyrosine Matabolism Phenylalanine
Ph l l i h d lPh l l i h d lPhenylketonuriaPhenylketonuriaTyrosine
TransaminaseTransaminase
Phenylalanine hydroylasePhenylalanine hydroylase
Thyroid hormonesIodinationIodinationOxidative couplingOxidative coupling
PhenylketonuriaPhenylketonuria
Tyrosinaemia type IITyrosinaemia type II
P hydroxyphenyl pyruvicP hydroxyphenyl pyruvic P hydroxyphenyl pyruvic
hydroxylasehydroxylaseDOPA
Tyrosine hydroxylaseTyrosine hydroxylase
Neonatal tyrosinaemiaNeonatal tyrosinaemia AlbinismAlbinism
Homogentisic acid
hydroxylasehydroxylase
Homogentisic oxidaseHomogentisic oxidaseDopamine
DOPA quinoneDecarboxylaseDecarboxylaseNeonatal tyrosinaemiaNeonatal tyrosinaemia
AlkaptonuriaAlkaptonuriaMalyl acetoacetate
IsomeraseIsomerase
Dopamine
Noradrenaline
DopachromeHydroxylaseHydroxylase
AlkaptonuriaAlkaptonuria
Fumaryl acetoacetate
Fumaryl acetoacetateFumaryl acetoacetatehydrolasehydrolase
Noradrenaline
MelanineTransmethylaseTransmethylase
Tyrosinaemia type ITyrosinaemia type I
AcetoacetateFumarate +
hydrolasehydrolaseAdrenaline
Tyrosinaemia type ITyrosinaemia type I
Prof Dr Mohammad Ibrahim Prof of Medical Biochemistry http://osp.mans.edu.eg/medbiochem_mi
١٢