The SNP mutation responsible for sickle-cell disease changes amino acid 6 in haemoglobin β from glutamic acid (E) to valine (V). 

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#Id: 6509

#Unit 7. System Physiology – Animal

Phenylketonuria (PKU) 

Mutation of the gene for phenylalanine hydroxylase

Caused by tetrahydrobiopterin (BH4) deficiency

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#Id: 6510

#Unit 7. System Physiology – Animal

Tyrosine is transported into catecholamine-secreting neurons via a Na+ - dependent carrier

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#Id: 6511

#Unit 7. System Physiology – Animal

Rate-limiting step in synthesis of catecholamines:  Tyrosine is converted to dihydroxy-phenylalanine (DOPA) by tyrosine hydroxylase

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#Id: 6512

#Unit 7. System Physiology – Animal

DOPA is converted to dopamine in the cytoplasm of the cells by DOPA decarboxylase (amino acid decarboxylase)

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#Id: 6513

#Unit 7. System Physiology – Animal

DOPA is converted to dopamine in the cytoplasm of the cells by DOPA decarboxylase (amino acid decarboxylase)

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#Id: 6514

#Unit 7. System Physiology – Animal

Dopamine is converted to norepinephrine by dopamine β -hydroxylase