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J Am Soc Nephrol

Title:		Control of oxalate formation from L-hydroxyproline in liver mitochondria
Author(s):		Takayama T; Fujita K; Suzuki K; Sakaguchi M; Fujie M; Nagai E; Watanabe S; Ichiyama A; Ogawa Y;
Address:		"Department of Urology, Research Equipment Center, Hamamatsu University School of Medicine, Hamamatsu, Japan. takayama@hama-med.ac.jp"
Journal Title:		J Am Soc Nephrol
Year:		2003
Volume:		14
Issue:		4
Page Number:		939 - 946
DOI:		10.1097/01.asn.0000059310.67812.4f
ISSN/ISBN:		1046-6673 (Print) 1046-6673 (Linking)
Abstract:		"Serine:pyruvate/alanine:glyoxylate aminotransferase (SPT/AGT) is largely located in mitochondria in carnivores, whereas it is entirely found within peroxisomes in herbivores and humans. In rat liver, SPT/AGT is found in both of these organelles, and only the mitochondrial enzyme is markedly induced by glucagon. Although SPT/AGT is a bifunctional enzyme involved in the metabolism of both L-serine and glyoxylate, its contribution to L-serine metabolism is independent of mitochondrial or peroxisomal localization (Xue HH et al., J Biol Chem 274: 16028-16033, 1999). Therefore, the species-specific and food habit-dependent organelle distribution might be required for proper metabolism of glyoxylate at the subcellular site of its formation. Glyoxylate formation from glycolate and that from L-hydroxyproline have been shown to occur in peroxisomes and mitochondria, respectively. The present study found that urinary excretion of oxalate was markedly increased when a large dose of L-hydroxyproline or glycolate was administered to rats. Oxalate formation from L-hydroxyproline but not that from glycolate was significantly reduced when mitochondrial SPT/AGT had been induced by glucagon. The hydroxyproline content of collagen is 10 to 13%, and collagen accounts for about 30% of total animal protein; therefore, these results suggest that an important role of mitochondrial SPT/AGT in carnivores is to convert L-hydroxyproline-derived glyoxylate into glycine in situ, preventing undesirable overflow into the production of oxalate"
Keywords:		"Animals Glucagon/metabolism Glyoxylates/*metabolism/urine Hydroxyproline/*metabolism Liver/enzymology Male Mitochondria, Liver/*metabolism Oxalates/*metabolism Rats Rats, Wistar Transaminases/metabolism;"
Notes:		"MedlineTakayama, Tatsuya Fujita, Kimio Suzuki, Kazuo Sakaguchi, Michiko Fujie, Michio Nagai, Erina Watanabe, Shinya Ichiyama, Arata Ogawa, Yoshihide eng Research Support, Non-U.S. Gov't 2003/03/28 J Am Soc Nephrol. 2003 Apr; 14(4):939-46. doi: 10.1097/01.asn.0000059310.67812.4f"