The first two errors appear in creatine biosynthesis as autosomal recessive deficiencies of arginine-glycine amidinotransferase
(AGAT) and guanidinoacetate methyltransferase (GAMT).
A creatina e um nutriente natural, de procedencia animal encontrada em carnes vermelhas e peixes (Gualano e colaboradores, 2008), derivado de tres aminoacidos: glicina, arginina e metionina (Torres-Leal e Marreiro, 2008; Cooper e colaboradores, 2012) e tres enzimas: L-arginina-glicina amidinotransferase
(AGAT), metionina adenosiltransferase (MAT) e guanidinoacetato metiltransferase (GAMT) que sao indispensaveis para a sintese de creatina (Cooper e colaboradores, 2012).
Guanidinoacetate and creatine plus creatinine assessment in physiologic fluids: an effective diagnostic tool for the biochemical diagnosis of arginine:glycine amidinotransferase
and guanidinoacetate methyltransferase deficiencies.
Decreased GAA, decreased GAA/crn ratio, and increased CRE/GAA ratio define the biochemical phenotype of arginine:glycine amidinotransferase
It is well known that the transfer of the amidino group of arginine to glycine to yield L-ornithine and guanidinoacetate (GM), which is catalyzed by L-arginine:glycine amidinotransferase
, represents the first of two steps in the biosynthesis of Cr.
The amino acid L-arginine is substrate to five groups of enzymes in mammalians (Figure 5), which include arginyltRNA synthetase, arginine:glycine amidinotransferase
, arginine decarboxylase, arginase, and nitric oxide synthase isoforms .
rat kidney L-arginine:glycine amidinotransferase
synthesis by creatine
(14) Additional branches of arg metabolism are mediated by: (a) nitric oxide synthases (NOSs) leading to production of nitric oxide (NO) and downstream nitrogenous compounds, (b) arg decarboxylase leading to agmatine and its related byproducts, and (c) arg:glycine amidinotransferase
leading to guanidinoacetic acid, the immediate precursor of creatine.
For instance, among identified targets were titan and mitochondrial glycine amidinotransferase
, two proteins known to occur in the low nanogram per milliliter range (4-6.8 ng/mL) in blood (Farrah a al.
These are deficiencies of arginine:glycine amidinotransferase
(EC 188.8.131.52), S-adenosyl-L-methionine:guanidinoacetate N-methyltransferase (GAMT; EC 184.108.40.206), and creatine transporter.
In the current study, the gene encoding L-arginine-glycine amidinotransferase
, a member of the creatinine biosynthesis pathway, was affected as early as the first day after treatment with cisplatin.