Wolverine Tube Inc., which shut its U.S. plumbing-tube business in 2007, sought bankruptcy protection after failing to restructure the company.

Wolverine, based in Huntsville, Alabama, cited assets of $115.6 million and liabilities of $237.5 million as of Oct. 3, in a filing dated yesterday in U.S. Bankruptcy Court in Wilmington, Delaware. Four affiliates also sought protection.

The company in 2007 shut factories that employed 440 full- time workers in Decatur, Alabama, and Booneville, Mississippi, after demand for copper plumbing declined in the U.S. as contractors switched to plastic.

“The debtors’ liquidity became increasingly constrained due to the steep rise and significant volatility in the prices of copper and other metals that are the core of the debtors’ business,” Harold M. Karp’s, Wolverine chief operating officer, said in court papers.

Copper for delivery in December rose 6.6 cents, or 1.8 percent, to $3.7995 a pound at 8:53 a.m. on the Comex in New York. Copper for delivery in three months climbed 1.8 percent to $8,345 a metric ton on the London Metal Exchange.