Encino bank holding company CU Bancorp will acquire downtown Los Angeles lender 1st Enterprise Bank in an all-stock deal, the banks announced Tuesday. CU Bancorp is the parent of California United Bank, a $1.4 billion-asset lender. Combined with 1st Enterprise, the bank will have about $2.2 billion in assets. Both banks are publicly traded. Holders of 1st Enterprise stock will receive about 1.3 shares of CU Bancorp stock for each of their current shares, valuing the bank at about $103 million. The deal, expected to close by the end of the year, is the latest in a string of bank mergers and acquisitions that have followed the end of the recession. Analysts and executives have said it is difficult for small lenders to be profitable while meeting stricter bank regulations enacted after the financial crisis. Shares of CU Bancorp closed up 32 cents or 1.8 percent to $18.51 in trading on the Nasdaq. Shares 1st Enterprise gained $2.40 or 11 percent to close at $24.15 on the over-the-counter market.