Comparison of Cu,Zn-Superoxide Dismutases of Clawed Frogs of the Genus Xenopus

A. V. Peskin^1,2 and S. D. Stolyarov¹

¹Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, ul. Vavilova 26, Moscow, 117808 Russia; fax: (095) 135-80-12; E-mail: peskin@ibrran.msk.su

²To whom correspondence should be addressed.

Submitted March 3, 1997.

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Isoenzyme profiles and thermal stability of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) of clawed frogs of genus Xenopus (X. laevis and X. borealis) were compared. Earlier the presence of an unusually thermolabile mutant Cu,Zn-SOD as well as normal enzyme was shown in X. laevis. Having confirmed the data, we further show that X. borealis contains only the thermolabile Cu,Zn-SOD. This suggested that a mutation in the Cu,Zn-SOD gene and genome duplication have occurred in the immediate predecessor of X. laevis. Later on the parent Cu,Zn-SOD gene was lost, leaving only the mutated form of Cu,Zn-SOD in X. borealis.

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KEY WORDS: superoxide dismutase, oxygen radicals, Xenopus, evolution.

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