During the mid-1970s to early 1980s, my laboratory was trying to isolate an angiogenic stimulator from tumors, the factor we called TAF [tumor angiogenic factor] in our notebooks. This was at a time when no angiogenic stimulators were known to exist, nor had any angiogenesis inhibitors been discovered. In fact, few, if any, colleagues believed that angiogenic proteins would ever be found.
"We used tumors grown in mice, and the purification procedure involved multiple steps, which took more than a month to complete a purification cycle. We could not obtain a pure protein, despite more than four years of work.
"Then, in early 1983, Michael Klagsbrun, an associate professor in my laboratory, and Yuen Shing, a new assistant professor, [both postdoctoral fellows when the project started] introduced a heparin Sepharose column into the procedure and almost immediately obtained a single band of purified protein, purified approximately 500,000-fold (Arrow).
"This was ...
