Finding Kobre & Kim’s efforts to isolate a newly hired partner from a potential conflict inadequate, a New York state judge has disqualified the firm from representing a client in an arbitration against former employees of Lehman Brothers Holdings Inc.

Manhattan Supreme Court Justice James Yates granted a motion (pdf) Thursday in Chernick v. Essex Equity Holdings USA, LLC, (pdf) 600995/2010, by the former Lehman employees to disqualify Kobre & Kim from representing Essex Equity Holdings USA LLC, which is pursuing a $285 million arbitration claim over the sale of auction-rate securities by the bank’s brokerage arm.