Snapping four days of gains, the Sensex at the Bombay Stock Exchange lost 120 points, or 0.6 percent, to close at 19,287, on profit-booking by investors, amid weak European markets, today. The Nifty at the National Stock Exchange fell 45 points, or 0.8 percent, to 5,871.Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.