Role of cathepsins B and D in proteolysis of yolk in the catfish Clarias gariepinus.

Yolk processing pathways vary in the oocytes of benthophil and pelagophil teleosts. The present study investigated the yolk processing pattern in the oocytes of the fresh water catfish Clarias gariepinus at vitellogenic, maturation, and ovulated stages. This study concludes that during maturation stage, an electrophoretic shift in the major peptide band on Polyacrylamide gel electrophoresis (PAGE) occurs due to a decrease in the size of the yolk protein.