EXHIBIT 2.1 WHEREVER CONFIDENTIAL INFORMATION IS OMITTED HEREIN (SUCH OMISSIONS ARE DENOTED BY AN ASTERISK), SUCH CONFIDENTIAL INFORMATION HAS BEEN SUBMITTED SEPARATELY TO THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL...Patent Purchase Agreement • March 24th, 1999 • Repligen Corp • Biological products, (no disgnostic substances) • Massachusetts
EXHIBIT 2.3 COLLATERAL ASSIGNMENT OF PATENTS THIS COLLATERAL ASSIGNMENT OF PATENTS (hereinafter referred to as the "Agreement"), dated as of March 9, 1999, by and between Repligen Corporation, a Delaware corporation (hereinafter referred to as the...Collateral Assignment of Patents • March 24th, 1999 • Repligen Corp • Biological products, (no disgnostic substances) • Massachusetts
