Lens transglutaminase and cataract formation.
AUTOR(ES)
Lorand, L
RESUMO
A protein polymer characteristically present in human cataract was shown to contain significant amounts of gamma-glutamyl-epsilon-lysine isopeptides. It is proposed that these crosslinks are produced by the action of transglutaminase (R-glutaminyl-peptide:amine-gamma-glutamyl-yltransferase, EC 2.3.2.13), which is all the more plausible because lens contains the enzyme and endogenous protein substrates for it. The enzyme is similar to that obtained from liver and is Ca2+ dependent. Highest apparent activity is found in lens cortex. When cortex homogenate from the rabbit was incubated in the presence of Ca2+ with either [14C]putrescine or with dansylcadaverine, a a selective incorporation of the radioactive or fluorescent amine into the heavier subunits (Mr approximately 26,000 and 30,000) of beta-crystallins could be demonstrated. Possible modes of regulating the crosslinking activity of this enzyme in lens are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=319129Documentos Relacionados
- Racemization in human lens: evidence of rapid insolubilization of specific polypeptides in cataract formation.
- Opacification of gamma-crystallin solutions from calf lens in relation to cold cataract formation.
- Allopurinol use and the risk of cataract formation.
- Influence of various miotics on cataract formation.
- Mechanisms of Cataract Formation in the Human Lens
