Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.2.3 (glutathione synthetase)
 678 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glutathione and its related enzymes were measured for normal and cataractous human lenses. Glutathione decreased progressively with the development of cataracts. This decrease was more pronounced in the nucleus than in the capsule-epithelia of cataractous lenses. Glutathione reductase in nuclear extracts was relatively unchanged during cataract progress, while glutathione synthetase was significantly low in the advanced stages of cataracts. gamma-Glutamylcysteine synthetase was not measurable in the nuclei of cataractous lenses.
 ...
PMID:Glutathione and glutathione-related enzymes in human cataractous lenses. 194 85

This investigation examined many parameters during the course of early development of naphthalene-induced cataract in a time span of 0 to 79 days of treatment. Feeding naphthalene daily to Black-Hooded rats resulted in gradual progressive development of cataract. The first faint opacities were detectable after 7 days. Free soluble total glutathione (oxidized and reduced) of these lenses was shown to gradually decrease to a maximum loss of about 20%, a value reached by day 30 of treatment. No activity loss of either enzyme required for glutathione synthesis (gamma-glutamylcysteine synthetase or glutathione synthetase) was observed in homogenates of naphthalene versus control lenses. There was also neither impairment of [35S]-L-cystine uptake nor of [35S]-glutathione synthetic capacity in lenses cultured from rats after 12, 24 or 36 days of naphthalene feeding when compared to control lenses. Hence, glutathione loss cannot be explained by a damaged glutathione synthesis system. Progressive activity loss of glutathione peroxidase and glutathione reductase was observed. The loss of glutathione peroxidase activity was especially remarkable. Thus, the defense system against oxidative damage is impaired and may be a significant factor in naphthalene-induced cataract of the rat.
 ...
PMID:Glutathione synthesis and glutathione redox pathways in naphthalene cataract of the rat. 196 27

The activities of five enzymes of glutathione metabolism were determined in lenses from cataract-resistant and cataract-prone (Emory) mouse variants at three different ages (5 weeks, 10 weeks and 6 months). The enzymes included those required for glutathione synthesis, gamma-glutamylcysteine synthetase and glutathione synthetase, as well as glutathione-S-transferase, glutathione peroxidase and glutathione reductase. The differences in the activities of the five enzymes in the two mouse variants were not remarkable at any of the three ages. Activity of each enzyme was noted to be in excess of the preceding one in this integrated metabolic pathway, with the exception of glutathione reductase. gamma-Glutamylcysteine synthetase appears to be the pacesetting enzyme of this metabolic scheme in the mouse lens. The activity of each enzyme was compared with that earlier reported for human, rabbit and dog lenses.
 ...
PMID:Glutathione metabolism in lenses of Emory and cataract-resistant mice: activity of five enzymes. 287 Aug 75

The activities of gamma-glutamylcysteine synthetase (gamma-GCS) and glutathione synthetase, the two enzymes responsible for glutathione synthesis, were determined in adult lenses from representative species of eight mammalian orders. Lenses from Old World higher simians, including man, exhibited remarkably low gamma-GCS activity when compared to a prosimian and the other seven orders. In contrast, glutathione synthetase activity was comparable and relatively high in all orders. This, together with knowledge of its known lability and control mechanisms, suggests that gamma-GCS is a critical enzyme in the lens of the aging higher primate, whose very low and rate-limiting activity is a latent factor in the development of age-related cataract.
 ...
PMID:Glutathione synthesis in evolution: an Achilles' heel of human and other old world simian lenses. 287 29

Six factors were analyzed which may be involved in the decline of glutathione synthesis in the aging lens and cataract, with special emphasis placed upon the human lens. The factors included: 1) lability of gamma-glutamylcysteine synthetase, 2) paucity of gamma-glutamylcysteine synthetase in primate lenses as compared to other mammalian lenses, 3) enzyme activity reduction with age in the human lens, 4) rate control by reactant scarcity, especially of cysteine and magnesium ion, 5) rate control by inhibition using 5'-AMP, 5'-ADP and glutathione, and 6) possible dissociation of the multi-enzyme complex. It was concluded that decline of the glutathione synthetic capacity in vivo would be most likely caused by reduction of gamma-glutamylcysteine synthetase activity rather than of glutathione synthetase activity.
 ...
PMID:Lenticular glutathione synthesis: rate-limiting factors in its regulation and decline. 614 Jan 27