Heparins are natural molecules that are used as blood thinners and are typically obtained from pig intestines or cow lungs. Synthetic preparation could avoid problems with contamination, which in 2008 killed more than 80 people in the United States.

Researchers led by Jian Liu at the University of North Carolina at Chapel Hill and Robert Linhardt at the Rensselaer Polytechnic Institute in Troy, New York, used a series of enzymes to synthesize a version of the drug in either 10 or 12 reaction steps. This is far fewer than a commercial chemical synthesis that involves around 50 steps. In addition, the two new syntheses have yields of 45% and 37%, respectively — a considerable improvement on current synthetic methods.

The authors say that their method could one day generate heparin efficiently and on an industrial scale.

Science 334, 498–501 (2011)