TY  - CHAP
M1  - Book, Section
TI  - Chapter 142. Disorders of Creatine and Ornithine Metabolism
A1  - Stockler-Ipsiroglu, Sylvia
A2  - Rudolph, Colin D.
A2  - Rudolph, Abraham M.
A2  - Lister, George E.
A2  - First, Lewis R.
A2  - Gershon, Anne A.
PY  - 2011
T2  - Rudolph's Pediatrics, 22e
AB  - Creatine  is  synthesized  mainly  in  the  liver  and  pancreas  by  the  action  of  arginine:glycine  amidinotransferase  (AGAT)  and  guanidinoacetate  methyltransferase  (GAMT)  with  arginine,  glycine,  and  S-adenosylmethionine  as  essential  substrates  (eFig.  142.1).  AGAT  catalyzes  the  first  of  the  two  reactions  involved  in  the  de  novo  synthesis  of  creatine.  This  reaction  utilizes  arginine  and  glycine  as  substrates  and  yields  guanidinoacetate  and  ornithine  as  products.  Guanidinoacetate  is  further  converted  to  creatine  by  the  action  of  GAMT,  using  S-adenosylmethionine  as  a  methyl  group  donor.  Creatine  reaches  muscle  and  brain  via  an  active  transmembrane  creatine  transport  system  (CRTR).  Creatine  is  then  utilized  in  the  cellular  pool  of  creatine/creatine-phosphate,  which  together  with  creatine  kinase  and  ATP/ADP  provides  a  high  energy  phosphate  buffering  system.  Intracellular  creatine  and  creatine  phosphate  are  nonenzymatically  converted  to  creatinine,  with  a  1.5%  constant  daily  turnover  rate  of  body  creatine.  Creatinine  is  excreted  in  urine,  and  the  daily  urinary  creatinine  excretion  is  directly  proportional  to  total  body  creatine.  
SN  - 
PB  - The McGraw-Hill Companies
CY  - New York, NY
Y2  - 2024/04/18
UR  - accesspediatrics.mhmedical.com/content.aspx?aid=6725439
ER  -