Lysine biosynthesis inMethanobacterium thermoautotrophicum is by the diaminopimelic acid pathway

Methanobacterium thermoautotrophicum, an archaebacterium, possesses the first and last enzymes of the diaminopimelic acid pathway for lysine biosynthesis, dihydrodipicolinate synthase, and diaminopimelate decarboxylase. It does not have saccharopine dehydrogenase, the last enzyme of the aminoadipate pathway for lysine biosynthesis. The dihydrodipicolinate synthase is inhibited but not repressed by lysine. We conclude that this microbe uses the diaminopimelate pathway for synthesis of lysine.Deceased.     

Rat striatal dopamine and tetrahydrobiopterin content following an intrastriatal injection of manganese chloride

Injection of manganese into the rat corpus striatum causes a rapid fall in the biopterin and dopamine (DA) content ipsilateral to the lesion. Two weeks after the lesion both biopterin and DA are partially recovered. Controls, injected with saline or magnesium, do not show alterations in their DA or cofactor levels. It is proposed that the fall in DA levels results from a rapid displacement of the amine from its storage sites by manganese followed by a decrease in the rate of DA synthesis causes by the drop in cofactor levels.     

Interaction of reduced glutathione with bovine brain tubulin

Incubation of phosphocellulose-purified tubulin with GSH at 30 degrees C results in an inhibition of colchicine binding activity. GSSG has a protective effect against the GSH-induced loss of colchicine-binding. Incubation of tubulin with GSH at 30 degrees C results in the formation of abnormal tubulin polymers which are insensitive to cold. Such aggregation is insensitive to antimicrotubular drugs. Aggregation is inhibited by GSSG but not by DTT or mercaptoethanol. GSH-induced aggregation is very sensitive to the ionic strength of the assembly medium; both the aggregation and colchicine binding inhibition induced by GSH are inhibited at higher ionic strength. These results indicate a very complex interaction of GSH with tubulin.