3-Hydroxyacyl-coa Dehydrogenase activity in fasted crayfish (orconectes virilis) hepatopancreas and flexor muscle tissues.

Abstract

Fatty acids are a major energy source in animal cells. Before fatty acids can be used as an energy source, they must be acylated in the cytosol and oxidized in the mitochondria. This oxidation pathway in the mitochondria is p-oxidation. The enzyme 3-hydroxyacyl-CoA dehydrogenase (HADH) catalyzes the third step of ~-oxidation. HADH activity was measured in crayfish, Orconectes virilis, to determine the effect of starvation. The samples were taken from the hepatopancreas and muscle of fed, three day fasted, five day fasted, and seven day fasted crayfish. The hepatopancreas and muscle tissue from each animal were homogenized and centrifuged to separate cytosolic and mitochondrial fractions. The HADH activity in the cytosol and mitochondria was measured. The results showed that no detectable activity in the cytosolic fraction. This suggested that HADH was not a cytosolic enzyme. The HADH activity in the hepatopancreas mitochondrial fractions showed inconclusive differences in the activity level among fasting periods. The mitochondrial fraction in muscle tissue, however, showed a noticeable increase in HADH activity with the length of the fasting period. Key words: 3-hydroxyacyl-CoA dehydrogenase; p-oxidation; hepatopancreas; Orconectes virilis.