5-aminolevulinate dehydratase activity in blood of rabbits given tin or lead.
نویسندگان
چکیده
The activity of 5-aminolevulinate dehydratase (ALAD) in rabbit blood is significantly inhibited by tin. Intravenous administration of tin (0.48 or 4.8 mumol/kg body weight) causes a decrease in the activity of the enzyme by 60% or 94% respectively. The effects of tin and lead on ALAD differ: inhibition by tin is not affected by pre-incubation at 50-60 degrees C, whereas the inhibitory effect of lead is increased by the same pretreatment. The optimum pH for rabbit blood ALAD is 6.8 in control rabbits. This optimum shifts to pH 5.8-6.0 in the blood of tin-treated rabbits, with or without pre-incubation at 60 degrees C for 5 min, while a similar shift is prevented by the same pre-incubation after lead treatment. Recovery to normal activity is faster after tin than after lead treatment.
منابع مشابه
Restoration of lead-inhibited 5-aminolevulinate dehydratase activity in whole blood by heat, zinc ion, and (or) dithiothreitol.
We examined effects of heat, zinc, ion, and dithiothreitol in restoring the activity of lead-inhibited-5-aminolevulinate dehydratase (EC 4.2.1.24). The ratio of non-activated to activated activity produced by dithiothreitol correlated well with blood lead concentration among 35 lead workers. The individual effects of heat, zinc, or dithiothreitol differ from each other in the shift of pH optimu...
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It is well know that exposure to lead causes disorders of porphyrin metabolism such as elevation of ƒÂ-aminolevulinic acid (ALA) and coproporphyrin (CP) in urine, accumulation of protoporphyrin (PROTO) in erythrocytes, and inhibition of erythrocyte ƒÂ-aminolevulinic acid dehydratase (ALAD) activity.') In addition, it has been reported that inorganic tin (II) also inhibits erythrocyte ALAD activ...
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ورودعنوان ژورنال:
- British journal of industrial medicine
دوره 36 4 شماره
صفحات -
تاریخ انتشار 1979