Protein Transporter Mechanisms

What is the product of the enzyme phenylalanine hydroxylase?

What is the deficiency of phenylalanine hydroxylase associated with?

What is the role of tetrahydrobiopterin (BH4) in the metabolism of phenylalanine?

What is the enzyme responsible for converting tryptophan to 5-hydroxytryptophan?

What is the product of the enzyme tryptophan hydroxylase?

What is the role of dihydropteridine reductase in the metabolism of phenylalanine?

What is the significance of the hypothalamus in the regulation of neurotransmitters?

What is the role of antipsychotics in the regulation of neurotransmitters?

What is the role of N-methyltransferase in the metabolism of neurotransmitters?

What is the significance of TRH (thyrotropin-releasing hormone) in the regulation of neurotransmitters?

Phenylalanine Metabolism

Phenylalanine is converted to tyrosine by phenylalanine hydroxylase, which requires tetrahydrobiopterin (BH4) as a cofactor.
Deficiency of phenylalanine hydroxylase leads to phenylketonuria.
Tyrosine can be converted to L-DOPA by tyrosine hydroxylase, which also requires BH4.
L-DOPA is converted to catecholamines, such as dopamine, norepinephrine, and epinephrine.

Neurotransmitters

Tryptophan is converted to 5-hydroxytryptophan by tryptophan hydroxylase, which also requires BH4.
5-Hydroxytryptophan is converted to serotonin (5-HT).
Norepinephrine is converted to epinephrine by N-methyltransferase.

Hormone Regulation

TRH (thyrotropin-releasing hormone) stimulates the release of TSH (thyroid-stimulating hormone) from the hypothalamus.
Dopamine, VIP (vasoactive intestinal peptide), and TRH are involved in regulating prolactin levels.
The hypothalamus and hypophyseal portal system are involved in regulating hormone levels.

Protein Transport

Facilitated diffusion is a type of carrier-mediated transport that requires a protein transporter.
Facilitated diffusion is saturable, meaning that there is a maximum transport rate.
The presence of a protein transporter is necessary for facilitated diffusion.
Simple diffusion does not require a protein transporter and has a linear relationship with solute concentration.

This quiz tests your understanding of protein transporters and their role in solute transport across the plasma membrane. It covers the concept of transport rate and its relationship with solute concentration.