Chicago, June 12 : James A. Johnson, the Washington insider whom Senator Barack Obama tapped to head his Vice-Presidential search effort, resigned abruptly to silence a growing furore over his business ties.

Johnson has been a fixture in Washington political and legal circles for three decades, and had led the Vice-Presidential search team for Senator John Kerry, the Democrats' Presidential nominee in 2004.

His departure on Wednesday would deprive Obama of decades of experience and access to Washington's power elite.

As quoted in the New York Times, his resignation, at the start of a general election contest in which the candidates have pledged to run issue-based campaigns.

Johnson also faced questions about his role on compensation committees that awarded large payouts to corporate executives.

Obama had defended Johnson as recently as Tuesday, saying that he had only a "tangential" role in the scandal.

But as questions about Johnson grew, Obama felt he had to move quickly to rid the campaign of a man who had come to symbolize the Washington fixers that Obama was running against.

Johnson, in a statement issued on Wednesday afternoon, said that he was leaving the campaign not because he had done anything wrong but to save Obama further grief.

Although Obama's campaign is known for its stability and cohesiveness, Johnson is the second high-profile adviser to step down in the wake of controversy. In March, Samantha Power, a close friend and foreign policy adviser, resigned after referring to Senator Hillary Rodham Clinton as "a monster."

Johnson, 64, is a native of Minnesota, is the vice chairman of Perseus, a 2 billion dollars private equity fund in Washington. (ANI)