Search

1. The possibility that temperature acclimation (to 10 or 18 degrees C for 28 days) would alter the cytochromes P-450 of rainbow trout was addressed. 2. The specific content of LM4b (P-450 IA1), the trout isozyme responsible for activation of polynuclear aromatic hydrocarbons, was lower in 18 degrees C fish than it was in 10 degrees C fish. 3. Kinetic analysis of aryl hydrocarbon hydroxylase indicated that, while thermal acclimation caused no change in Vmax, it lowered the apparent Km of this enzyme for benzo[a]pyrene when assayed at acutely shifted temperatures. 4. Thermal acclimation of fish may have significance when feral populations are subjected to acute temperature shifts.

Chromatofocusing between pH 7.4 and 5.0 was introduced as a final step for the resolution of multiple forms of cytochrome P-450 from control, phenobarbital and 3-methylcholanthrene-pretreated rat liver microsomal fractions. Altogether, chromatofocusing produced 21 P-450-containing pools, which differed from each other with respect to substrate specificity, spectral maximum and elution pH. Aryl hydrocarbon (benzo(a)pyrene) hydroxylase (AHH) activity was concentrated into low pI pools in all animal groups. 7-Ethoxycoumarin O-deethylase (ECOD) activity comigrated with AHH activity throughout the purification procedure. Aminopyrine N-demethylase (APND) activity was spread into several pools with forms of both low and high pI proteins.

Aryl hydrocarbon hydroxylase (AHH) has been measured in the skin, jejunum and liver of normal and psoriatic individuals. We have been unable to confirm previous reports of an abnormality in AHH activity in patients with psoriasis. Re-examination of the laboratory records on which the original reports were based leads us to doubt their veracity and validity.