Adaptative features of enzymes from family sciaenidae (Perciformes)--I. Studies on soluble malate dehydrogenase (s-MDH) and creatinine kinase (CK) of fishes from the south coast of Uruguay.

1. Electrophoretic analysis of the soluble malate dehydrogenase (s-MDH) and creatine kinase (CK) isozyme patterns of three species of temperate fishes (Scianidae, Perciformes) indicates at least two loci for s-MDH, Mdh-A and Mdh-B, and four CK, Ck-A, Ck-B, Ck-C and Ck-D. 2. The subunits encoded by these loci occurred at different levels in different tissues and organs analyzed. 3. Through electrophoretic analysis the products of these loci showed different behaviour to changes in temperature. 4. Relative activities of s-MDH and CK isozymes were compared by Klebe's (1975) method to determine pattern of divergence of duplicated gene expression in the three studied species.

Adaptative features of enzymes from family sciaenidae--II. Studies on phosphoglucose isomerase (PGI) of fishes from the south coast of Uruguay.

1. The electrokinetic and thermostability properties of phosphoglucose isomerase (PGI) in three species of temperate fishes (Perciformes, Acanthopterygii)--Cynoscion striatus, Macrodon ancylodon and Micropogonias furnieri--have been analyzed in order to study the adaptative 2. Unlike most diploid fishes the PGI of these species seemed to be encoded by three PGI loci. 3. The subunits encoded by these loci occurred at different levels in the different tissues and organs analyzed. 4. Genetic variants at two loci (Pgi-A and Pgi-B2) were detected in Cynoscion striatus, and at one (Pgi-A) in Micropogonias furnieri. 5. The product of these loci could be separated in three PGI regions based on their electrophoretic distribution and thermostability properties. 6. The more anodal region (including isozymes and allozymes) was more thermolabile than the less anodal one, which is predominant in a single tissue skeletal muscle. 7. Relative activities of PGI isozymes were compared by Klebe's method to determine pattern of divergence of duplicated gene expression in the three species studied.

Adaptative features of enzymes from family Sciaenidae--III. Studies on lactate dehydrogenase (LDH) of fishes from the south coast of Uruguay.

1. Electrophoretic analyses of lactate dehydrogenase isozyme patterns of three species of temperate fish belonging to family Sciaenidae (order Perciformes) indicates that at least three LDH loci--Ldh-A, Ldh-B and Ldh-C are active. 2. The subunits encoded by these loci occurred at different levels in the different tissues and organs analyzed. 3. The products of these loci show different response to changes in temperature. The results were obtained by electrophoretic analyses. 4. Thermostability of skeletal muscle, heart and eye lactate dehydrogenase incubated at 60 degrees C for different periods of time were examined. 5. Relative activities of LDH isozymes were compared by Klebe's method to determine pattern of divergence of duplicated gene expression in the three species studied.