Disease relevance of Cth

• Sequence of cDNA for rat cystathionine gamma-lyase and comparison of deduced amino acid sequence with related Escherichia coli enzymes [1].
• Male Wistar rats were subjected to acute endotoxemia (Escherichia coli lipopolysaccharide (LPS) 6 mg kg(-1) intravenously (i.v.) for 6 h) and treated with vehicle (saline, 1 ml kg(-1) i.v.) or DL-propargylglycine (PAG, 10-100 mg kg(-1) i.v.), an inhibitor of the H2S-synthesizing enzyme cystathionine-gamma-lyase (CSE) [2].
• L-Cysteine, a substrate of cystathionine-gamma-lyase (CSE), decreased vasoconstriction in normal rat livers (P < .05) but failed to do so in livers with cirrhosis [3].
• The present study was designed to explore the possible effect of L-arginine on endogenous hydrogen sulfide/cystathionine-gamma-lyase (H(2)S/CSE) pathway in the pathogenesis of pulmonary hypertension and pulmonary vascular structural remodeling induced by high pulmonary blood flow [4].
• This work showed that gene expression of cystathionine gamma-lyase (CSE), a H(2)S generating enzyme, and the activity of CSE in thoracic aorta were suppressed in hypertension rats [5].

High impact information on Cth

• Impairment of biliary excretion was accompanied by decreased steady-state hepatic levels of gamma-glutamyl cysteine synthetase and gamma-cystathionase messenger RNAs [6].
• We observed an increase in the activities of the hepatic transsulfuration enzymes (cystathionine beta-synthase and cystathionine gamma-lyase) in the untreated diabetic rat [7].
• Three candidates for an epitope common to probasin and PRB-RA were found on close examination of the amino acid sequences of the two proteins [8].
• These results show that PRB-RA/cystathionase is neither structurally nor functionally related to probasin except for a common epitope and that cystathionase, a cystein-producing enzyme, is localized in urinary tubular epithelial cells in a highly restricted region of the kidney in addition to in liver parenchymal cells [8].
• A sequence homology search revealed that PRB-RA is almost completely identical to rat cystathionine gamma-lyase (cystathionase) and that it does not show overall homology with probasin [8].

Chemical compound and disease context of Cth

• Impact of L-arginine on hydrogen sulfide/cystathionine-gamma-lyase pathway in rats with high blood flow-induced pulmonary hypertension [4].
• The results of studies on the substrate specificities of elimination and replacement reactions allowed insight into the active and regulatory sites of Streptomyces phaeochromogenes cystathionine gamma-lyase (L-cystathionine cysteine-lyase (deaminating), EC 4.4.1.1) [9].

Biological context of Cth

• The amino acid sequence deduced from the determined cDNA sequence included sequences identical with those of proteolytic fragments of PRB-RA, which covered about 70% of the deduced sequence [8].
• In conclusion, the lack of gamma-cystathionase activity in over 50% of old lenses is due to decreased gene expression and proteolytic degradation of the oxidized enzyme [10].
• Oxidative stress targeted gamma-cystathionase in the eye lens upon aging, since the enzyme contained more carbonyl groups in old lenses than in young ones. gamma-Cystathionase mRNA was also markedly reduced in old lenses, thus contributing to the age-associated deficiency in gamma-cystathionase [10].
• A cDNA clone for cystathionine gamma-lyase was isolated from a rat cDNA library in lambda gt11 by screening with a monospecific antiserum [1].
• There was only low gamma-cystathionase activity in H. diminuta and again the enzyme showed a range of substrate specificities [11].

Anatomical context of Cth

• The aims of this study were: (1) to investigate the mechanism that causes the age-related deficiency in gamma-cystathionase activity in the eye lens, and (2) to determine the role of gamma-cystathionase deficiency in cataractogenesis [10].
• Role of the transsulfuration pathway and of gamma-cystathionase activity in the formation of cysteine and sulfate from methionine in rat hepatocytes [12].
• 1. Methionine adenosyltransferase (ATP:L-methionine-S-adenosyl transferase, EC 2.5.1.6), cystathionine beta-synthase F1L-serine hydro-lyase (adding homocysteine), EC 4.2.1.22] and cystathionine gamma-lyase [L-cystathionine cysteine-lyase (deaminating), EC 4.4.1.1] activities were found only in the cytosol fraction of rat liver cells [13].
• Cystathionine gamma-lyase activity in the liver of dams and fetuses decreased to about 2-4% of that of control rats at 15 hrs after L-proparglyglycine injection, and that in the kidney and pancreas of dams to about 10-20% of that of control rats [14].
• 2. Polymorphs, lymphocytes (with admixed monocytes) and mixed bone marrow white cells contained no methionine adenosyl transferase, cystathionine beta-synthase or cystathionine gamma-lyase activities [13].

Associations of Cth with chemical compounds

• Cystathionine gamma-lyase catalyzed alpha, gamma elimination of selenocystathionine to yield alpha-ketobutyrate, selenocysteine, and NH3 [15].
• Thus, selenocysteine is synthesized from selenohomocysteine and cystathionine beta-synthase and cystathionine gamma-lyase reactions [15].
• To assess relations between vitamin B-6 and transsulfuration, we evaluated the effects of dietary pyridoxine (PN) on the hepatic concentration of relevant metabolites and in vitro activity of CBS and CGL [16].
• These findings indicated that at least one reason of the high content of cystathionine in the 3 weeks rat cerebellum was due to the low level of cystathionine gamma-lyase [17].
• We previously found that a deficiency in gamma-cystathionase activity may be responsible for glutathione depletion in old lenses [10].

Physical interactions of Cth

• A cystine-dependent inactivator of tyrosine aminotransferase co-purifies with gamma-cystathionase (cystine desulfurase) [18].

Other interactions of Cth

• We have investigated selenocysteine (2-amino-3-hydroselenopropionic acid) synthesis with cystathionine beta-synthase (EC 4.2.1.22) and cystathionine gamma-lyase (EC 4.4.1.1) of rat liver [15].
• Cystathionine gamma-lyase activity in liver decreased to about 4% of that of control rats 24 h after the DL-propargylglycine injection, and alanine aminotransferase activity decreased to about 35% of that of control rats [19].
• Incubation with an inhibitor of gamma-cystathionase (propargylglycine) prevented inactivation of tyrosine aminotransferase [20].
• When rats were fed a 10% casein diet containing 2% methionine, the activities of methionine adenosyltransferase, cystathionine beta-synthase, and cystathionine gamma-lyase, which participate in the methionine metabolism in the transsulfuration pathway, were significantly enhanced [21].
• The sulfane sulfur pool, a source of sulfur transferred by rhodanese, can be augmented in vitro in guinea pig liver, but not in rat liver when 3-mercaptolactate-cysteine disulfide is used as a substrate of gamma-cystathionase [22].

Analytical, diagnostic and therapeutic context of Cth

• Cystathionine gamma-lyase content in the various regions of week-3 rat brain estimated by immunoblotting was consistent with the enzyme activity, and the enzyme level in the cerebellum was lower than that in the other regions [17].
• A synthetic peptide, TYFRRI, corresponding to one of the candidates, neutralized the reactivity of the anti-probasin monoclonal antibody to both probasin and PRB-RA on Western blot analysis [8].
• Identification of probasin-related antigen as cystathionine gamma-lyase by molecular cloning [8].
• The effect of concentrations of sulfur-containing amino acids, activities of cystathionine gamma-lyase and cystathionine beta-synthase, and level of vitamin B6 were examined following menthionine administration in normal rats and chronically uremic rats with 7/8 nephrectomy [23].
• Hepatic gamma-cystathionase activity at 12 h after the intraperitoneal injection decreased in proportion to the amount of D,L-propargylglycine administered, but hepatic cystathionine beta-synthase activity did not change [24].

References