Protalix BioTherapeutics, Inc. (NYSEAMERICAN:PLX) is among the hidden penny stocks to buy now. During the first quarter, Goldman Sachs Group Inc. expanded its holdings in Protalix BioTherapeutics, Inc. (NYSEAMERICAN:PLX) by a whopping 482.3%. Following the purchase of 239,751 shares, the global investment bank now owns 289,461 shares of the company’s stock, valued at approximately $741,000. Investing in Protalix BioTherapeutics, Inc. (NYSEAMERICAN:PLX) is like planting a tree; with time and patience, it o ...