Selenophosphate is the active selenium-donor compound required by bacteria and mammals for the specific synthesis of Secys-tRNA, the precursor of selenocysteine in selenoenzymes. Although free selenide can be used in vitro for the synthesis of selenophosphate, the actual physiological selenium substrate has not been identified. Rhodanese (EC ) normally occurs as a persulfide of a critical cyste...

Previous studies have reported an association between Leber's optic neuropathy and deficiency of rhodanese activity in liver and rectal mucosa. We have studied the rhodanese isozymes in liver biopsies from three subjects with Leber's optic neuropathy. The rhodanese isozyme patterns were indistinguishable from controls both in relative intensity and position on the isoelectric focusing pH gradie...

When the enzyme rhodanese was partially digested by immobilized trypsin, it retained greater than 50% of its original activity although less than 10% of the undigested enzyme remained. The predominant daughter species were two 31-kDa polypeptides whose amino termini corresponded to either residue 44 or 45 of the enzyme's sequence. Following digestion, charged species were isolated by ion exchan...

The enzyme rhodanese is greatly stabilized in the range pH 4-6, and samples at pH 5 are fully active after several days at 23 degrees C. This is very different from results at pH greater than 7, where there is significant loss of activity within 1 h. A pH-dependent conformational change occurs below pH 4 in a transition centered around pH 3.25 that leads slowly to inactive rhodanese at pH 3 (t ...

This study was undertaken to investigate the relationships between stage of embryonic development and early posthatch growth and the level of rhodanese (thiosulfate:cyanide sulfurtransferase) activity in different regions of the digestive tract and liver of chickens. The embryos were studied at 14, 17, and 20 d and chickens were 1, 2, and 3 wk old. All tissues studied contained rhodanese. The h...

We have proposed that phosphorylated and dephosphorylated forms of the mitochondrial sulfurtransferase, rhodanese, function as converter enzymes that interact with membrane-bound iron-sulfur centers of the electron transport chain to modulate the rate of mitochondrial respiration (Ogata, K., Dai, X., and Volini, M. (1989) J. Biol. Chem. 204, 2718-2725). In the present studies, we have explored ...

Although rhodanese activity occurs in many tissues (l-3), the enzyme had been obtained in crystalline form from beef liver only (4). Beef kidney rhodanese could not be crystallized by the same procedure (5). To extend the biochemical genetic comparison reported previously (5), however, it was desired to obtain the kidney enzyme in a very high state of purity. This paper reports the purification...

Rhodanese is the major detoxifying enzyme for cyanide and requires sulphur for its action. Allium cepa (Onion) is rich in organosulphur which may serve as an antidote for cyanide poisoning by supplying sulphur to the enzyme rhodanese. The possible effects of Allium cepa on rhodanese activity during cyanide toxicity was investigated in male Wistar rats. Sixty Wistar rats (150-180 g) were divided...

Rhodanese (EC 2.8.1.1), a mitochondrial thiosulphate sulphurtransferase, is involved in the formation of iron-sulphur complexes and cyanide detoxification. By screening a rat liver cDNA library with oligonucleotide probes complementary to portions of the published bovine rhodanese peptide sequence, rat rhodanese cDNA clones were obtained and sequenced. Comparison of the rat rhodanese cDNA open ...

This work aimed to investigate the effect of lipoic acid (LA) on sulfane sulfur (S(*)) level and rhodanese activity in rat tissues. In vitro studies conduced so far have indicated that dihydrolipoic acid serves as an S(*) acceptor in the rhodanese-catalyzed S(*) transfer. This study revealed a significant increase in S(*) level and rhodanese activity in the heart, liver and kidney homogenates f...