Negatively charged amino acids have four ionisations zones

1. 1--------pK1 – charge +1

2. pK1---------pKr charge 0

3. pKr---------pK2 charge -1

4. pK2---------14 charge -2

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#Unit 7. System Physiology – Animal

Principal catecholamines synthesized by the adrenal medulla:

Norepinephrine

Epinephrine

Dopamine

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#Unit 7. System Physiology – Animal

Norepinephrine is formed by hydroxylation and decarboxylation of tyrosine

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#Unit 7. System Physiology – Animal

Some of the tyrosine is formed from phenylalanine, by Phenylalanine hydroxylase

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#Unit 7. System Physiology – Animal

Tetrahydrobiopterin (BH4) is a cofactor for tyrosine hydroxylase and phenylalanine hydroxylase

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#Unit 7. System Physiology – Animal

Phenylketonuria (PKU) 

Mutation of the gene for phenylalanine hydroxylase

Caused by tetrahydrobiopterin (BH4) deficiency

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#Unit 7. System Physiology – Animal

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