Biochemical Study of Rhodanese Enzyme Isolated from Blood and it’s Role in Cyanide Detoxification

This research included isolation of rhodanese enzyme from blood plasma. The modification method for isolation rhodanese from plasma in form of pure crystals showed highly purification folds compared with the gel filtaration technique which used to isolate rhodanese from ammonium sulphate precipitate solution of blood plasma. It
had been found that the protein peak (A) isolated from plasma and protein peak (C) isolated from ammonium sulphate precipitate solution of plasma with (65%) saturation by gel filtaration technique using (Sephadex G-75) had apparent molecular weight (37153 1000 Dalton) and (36307 1000 Dalton) respectively.
The study of optimal condition of rhodanese activity for the isolated protein peaks (A) and (C) showed optimum reaction time at (30), (35) minutes, optimal pH at (8), optimal temperature (45C),(50C) and optimal concentration (125mM) (130mM) of sodium thiosulphate and potassium cyanide(130mM), (135mM).
The results showed that benzaldehyde inhibit rhodanese activity and this inhibition can be removed partially by using (0.1M) sodium thiosulphate. It had been found a decrease of rhodanese activity when sodium thiosulphate replaced with amino acids (cysteine, methionine, cystine). The results showed that - mercapto ethanol break down both of protein peak (A) and (C) to a symmetrical peaks with different molecular weights.
The study of rhodanese activity which isolated from plasma (peak A) in cyanide detoxification in vivo (using experimental animals) and in vitro (using blood) in addition to the effect of cyanide on some clinical parameters levels like glucose, hemoglobin, and thiocyanate. The results showed that potassium cyanide leading to increase in glucose, hemoglobin and thiocyanate concentrations in vivo and in vitro compared with control group, while sodium thiosulphate and rhodanese or both are act in cyanide detoxification in vivo and in vitro and this was concluded through decrease of glucose and hemoglobin concentration and an increase of thiocyanate concentration compared with control group.