Methionine synthase activity and sulphur amino acid levels in the rat liver tumour cells HTC and Phi-1

2002 ◽  
Vol 63 (3) ◽  
pp. 381-391 ◽  
Author(s):  
Susan H Kenyon ◽  
Catherine J Waterfield ◽  
John A Timbrell ◽  
Anna Nicolaou
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Tumour Cells ◽  
Liver Tumour ◽  
Methionine Synthase ◽  
Sulphur Amino Acid ◽  
Amino Acid Levels

scholarly journals Determination of D-Amino Acid Oxidase Activity in Tumour Cells

2002 ◽  
Vol 39 (6) ◽  
pp. 595-598 ◽  
Author(s):  
Taizo Sasamura ◽  
Akihiko Matsuda ◽  
Yukifumi Kokuba
Keyword(s):  
Amino Acid ◽  
Cancer Patients ◽  
Rat Liver ◽  
Rat Kidney ◽  
Tumour Cells ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Tissue Samples ◽  
Host Tissues

Background We evaluated the assay for determining D-amino acid oxidase (DAAO) activity in tumour cells, rat liver and rat kidney for studying the effects of D-amino acid-containing solution on cancer patients. Methods and Results In this method the amount of ammonia produced by the DAAO activity after removal of endogenous ammonia using a Sephadex G25 column was determined. The highest activity was observed in rat kidney, which was almost eight times that found in rat liver. As compared with host tissues, the DAAO activity in tumour cells was considerably less. Conclusions This DAAO assay may be useful for analysis of various tissue samples as well as tumour cells.

Total Free Amino Acid Levels in Adult and Senescent Rat Liver

Gerontology ◽  
1978 ◽  
Vol 24 (1) ◽  
pp. 32-36 ◽  
Author(s):  
R.L. Eichholz ◽  
D.E. Buetow
Keyword(s):  
Amino Acid ◽  
Free Amino Acid ◽  
Rat Liver ◽  
Free Amino ◽  
Total Free Amino Acid ◽  
Amino Acid Levels

Effect of hydrazine upon vitamin B12-dependent methionine synthase activity and the sulphur amino acid pathway in isolated rat hepatocytes

1999 ◽  
Vol 57 (11) ◽  
pp. 1311-1319 ◽  
Author(s):  
Susan H Kenyon ◽  
Catherine J Waterfield ◽  
Daniel S Asker ◽  
Mariko Kudo ◽  
David W Moss ◽  
...  
Keyword(s):  
Amino Acid ◽  
Vitamin B12 ◽  
Rat Hepatocytes ◽  
Methionine Synthase ◽  
Isolated Rat Hepatocytes ◽  
Sulphur Amino Acid ◽  
Acid Pathway ◽  
Isolated Rat

Sulphur Amino Acid Levels in Some Tissues of the Rat during Pregnancy and Lactation

1987 ◽  
Vol 31 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Dolores López-Tejew ◽  
Marçal Pastor-Anglada ◽  
Xavier Remesar
Keyword(s):  
Amino Acid ◽  
Sulphur Amino Acid ◽  
Pregnancy And Lactation ◽  
Amino Acid Levels

Sulphur amino acid derivatives as inhibitors of vitamin B12 dependent methionine synthase

1996 ◽  
Vol 24 (2) ◽  
pp. 265S-265S ◽  
Author(s):  
SUSAN H. KENYON ◽  
MARIO ALVES ◽  
HENDRIK NEUBERT ◽  
ANNA NICOLAOU ◽  
ESTHER DEL OLMO ◽  
...  
Keyword(s):  
Amino Acid ◽  
Vitamin B12 ◽  
Methionine Synthase ◽  
Amino Acid Derivatives ◽  
Sulphur Amino Acid

scholarly journals Differential regulation of glutamate–cysteine ligase subunit expression and increased holoenzyme formation in response to cysteine deprivation

2005 ◽  
Vol 393 (1) ◽  
pp. 181-190 ◽  
Author(s):  
Jeong-In Lee ◽  
Joann Kang ◽  
Martha H. Stipanuk
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Catalytic Efficiency ◽  
Molar Ratio ◽  
Glutamate Cysteine Ligase ◽  
Sulphur Amino Acid ◽  
Low Protein ◽  
Subunit Expression ◽  
Amino Acid Intake ◽  
Activity State

GCL (glutamate–cysteine ligase) is a heterodimer of a GCLC (GCL catalytic subunit) that possesses all of the enzymatic activity and a GCLM (GCL modifier subunit) that alters the Ki of GCLC for GSH. We hypothesized that the expression of GCLM and the association of GCLM with GCLC were responsible for the apparent increase in GCL activity state observed in the liver of rats fed low-protein diets or in hepatocytes cultured in low-sulphur amino acid-containing medium. Therefore we conducted a series of studies using rats and a human hepatoma (HepG2/C3A) cell line to assess the role of GCLM and holoenzyme formation in the regulation of GCL activity in response to sulphur amino acid intake or availability. Increases in GCL activity in rat liver, as well as in HepG2 cells, were due to the additive effects of changes in the amount of GCLC and the kcat for GCLC. The increase in the kcat for GCLC was associated with increased holoenzyme formation, which was associated with an increase in the molar ratio of GCLM to GCLC. Furthermore, our results indicate that the GCLM level in rat liver is always limiting and that up-regulation of the GCLM level results in increased holoenzyme formation and an increase in the kcat. This is the first report demonstrating that the catalytic efficiency of rat GCL is increased by holoenzyme formation and the first demonstration of differential up-regulation of the GCL subunits in response to cysteine deprivation.

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