NEW YORK ( TheStreet) -- Protalix BioTherapeutics (AMEX: PLX) is trading at unusually high volume Tuesday with 1.7 million shares changing hands. It is currently at 4.1 times its average daily volume and trading down 61 cents (-8.8%) at $6.34 as of 2:15 p.m. ET. Protalix BioTherapeutics has a market cap of $634.8 million and is part of the health care sector and drugs industry. Shares are up 41% year to date as of the close of trading on Monday. Protalix BioTherapeutics, Inc., a biopharmaceutical company, through Protalix Ltd., focuses on the development and commercialization of recombinant therapeutic proteins based on its proprietary ProCellEx protein expression system in the United States. The company has a P/E ratio of 16.3, equal to the average drugs industry P/E ratio and below the S&P 500 P/E ratio of 17.7. TheStreet Ratings rates Protalix BioTherapeutics as a sell. Among the areas we feel are negative, one of the most important has been generally deteriorating net income. You can view the full Protalix BioTherapeutics Ratings Report. See all heavy volume stocks in our stocks moving on unusual volume list or get investment ideas from our investment research center.