Enron Corp. on Friday laid off 200 employees at its prized power trading unit to maintain a cost effective operation while in bankruptcy, a company spokesman said.

Workers ranging from traders and marketers to schedulers and billing specialists were let go from the company's natural gas and electricity trading unit, Enron Americas, said spokesman Mark Palmer.

"It's unfortunate, but we do need to make sure our costs are in line with the business and that we're able to protect the business going forward as much as possible," Palmer said.

Friday's cuts were the first significant cuts made to the wholesale trading unit, he said. That unit, the chief moneymaker for the once-mighty energy trader, is the main business Enron hopes will emerge intact from its massive Chapter 11 bankruptcy with a bank or other partner on board.

The company sought bankruptcy protection on Sunday.

The laid off workers will receive a $4,500 severance package, as will 4,000 let go Monday from the company's Houston headquarters. Last week Enron laid off about 1,100 workers from its London operation.

Enron has cut 25 percent of its 21,000-member work force in the past two weeks.