GTP cyclohydrolase I
GTP cyclohydrolase I (GTPCH) (EC 3.5.4.16) is a member of the GTP cyclohydrolase family of enzymes. GTPCH is part of the folate and biopterin biosynthesis pathways. It is responsible for the hydrolysis of guanosine triphosphate (GTP) to form 7,8-dihydroneopterin triphosphate (7,8-DHNP-3'-TP, 7,8-NH2-3'-TP).
Gene
GTPCH is encoded by the gene GCH1. Several alternatively spliced transcript variants encoding different isoforms have been described; however, not all of the variants give rise to a functional enzyme.
Clinical significance
Mutations in this gene are associated with malignant phenylketonuria (PKU) and hyperphenylalaninemia (HPA), as well as L-DOPA (Levodopa)-responsive dystonia.
Function
The transcribed protein is the first and rate-limiting enzyme in tetrahydrobiopterin (THB, BH4) biosynthesis, catalyzing the conversion of GTP into 7,8-DHNP-3'-TP. THB is an essential cofactor required by the aromatic amino acid hydroxylase (AAAH) and nitric oxide synthase (NOS) enzymes in the biosynthesis of the monoamine neurotransmitters serotonin (5-hydroxytryptamine (5-HT)), melatonin, dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), and nitric oxide (NO), respectively.
Podcasts:
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by Cash Ny
Dreams Of Venus
by: Catch 22Broken homes as far as the eye can see.
Bird's eye view: An ocean surrounded by
cubicles and fast food restaurants with nothing
but standard utility vehicles and smog in-between.
No one knows who is in control but underneath
them lies a bottomless pit. Everyone clings to
the sides and they use one another to reach the
crown of it. It's getting oh so dark in here now.
He's grabbing at my ankles. I'm grabbing at his.
Don't let go! Until all that's left of dreams of Venus.
The appendix of a system that doesn't need us.
One machine tells the other not to feed us.
They only want more. We only want more.
We're all getting nowhere confused.
Which way is up? Which way is down? I'm falling down.
I wonder which moment I decided to care?
Decided to wear the burdens of thousands of years.
We all live life like the sun and the moon
fucking in the afternoon.
The light it doesn't get through but it gets by.
One machine tells the other not to feed them.
They only want more. We only want more. Just let go.