Comparison of OUC enzyme activities between juveniles and adults
| . | Enzyme activity (μmol min-1 g-1) . | . | . | . | |||
|---|---|---|---|---|---|---|---|
| . | . | Adult . | . | . | |||
| . | Whole juvenile . | Liver . | Muscle . | Whole* . | |||
| CPSase III | 0.028±0.002 | 0.50±0.02 | 0.005±0.0005 | 0.015 | |||
| OTCase | 42.9±9.1 | 72.3±23.1 | 0.92±0.13 | 2.35 | |||
| Arginase | 22.1±1.9 | 12.3±2.9 | |||||
| GSase (transferase assay) | 3.5±0.5 | 7.0±3.1 | 0.29±0.06 | 0.425 | |||
| GSase (biosynthetic rate) | 0.175 | 0.35 | 0.015 | 0.021 | |||
| Urea-N flux rate† | 0.008 | 0.0008 | |||||
| . | Enzyme activity (μmol min-1 g-1) . | . | . | . | |||
|---|---|---|---|---|---|---|---|
| . | . | Adult . | . | . | |||
| . | Whole juvenile . | Liver . | Muscle . | Whole* . | |||
| CPSase III | 0.028±0.002 | 0.50±0.02 | 0.005±0.0005 | 0.015 | |||
| OTCase | 42.9±9.1 | 72.3±23.1 | 0.92±0.13 | 2.35 | |||
| Arginase | 22.1±1.9 | 12.3±2.9 | |||||
| GSase (transferase assay) | 3.5±0.5 | 7.0±3.1 | 0.29±0.06 | 0.425 | |||
| GSase (biosynthetic rate) | 0.175 | 0.35 | 0.015 | 0.021 | |||
| Urea-N flux rate† | 0.008 | 0.0008 | |||||
Juvenile measurements are based on whole fish while adults were based on livers (Anderson and Walsh,1995) and muscle (Walsh et al., 2003; Julsrud et al.,1998). Adult whole fish values are calculated based on the approximation that total toadfish biomass is 2% liver and 98% muscle. The GSase biosynthetic rate is calculated from the transferase rate, as in Anderson and Walsh (1995). Additionally, urea-N excretion rates are compared between adults (in Wood et al., 2003) and juveniles.
Enzyme rates are reported as means ± S.E.M. (N=6 for juveniles; N=3 for adult livers; N=8 for adult GSase muscle activity; N=4 for adult CPSase and OTCase muscle activity).
Whole body enzyme activities assume a 50 g fish with a liver to muscle ratio of 50:1.
Urea-N excretion rates expressed as μmol min-1g-1.