NURSING ANM AND GNM

Detailed explanation-1: -Tyrosine is a nonessential amino acid the body makes from another amino acid called phenylalanine. It is an essential component for the production of several important brain chemicals called neurotransmitters, including epinephrine, norepinephrine, and dopamine.

Detailed explanation-2: -Among the catecholamines are dopamine, epinephrine (adrenaline), and norepinephrine (noradrenaline). All catecholamines are synthesized from the amino acid l-tyrosine according to the following sequence: tyrosine → dopa (dihydroxyphenylalanine) → dopamine → norepinephrine (noradrenaline) → epinephrine (adrenaline).

Detailed explanation-3: -Epinephrine is synthesized starting with the amino acid tyrosine, which is converted to dihydroxyphenylalanine (DOPA) by the enzyme tyrosine hydroxylase. This is the rate-limiting step in the synthesis of norepinephrine and epinephrine and is tightly regulated at multiple levels.

Detailed explanation-4: -The amino acid tyrosine is the precursor for all three catecholamines. The first step in this reaction pathway, catalyzed by tyrosine hydroxylase, is rate-limiting. Dopamine is produced by the action of DOPA decarboxylase on DOPA (see Figure 6.11).