A benzamidine is the aromatic amidine C6H5C(NH)NH2, which is used in protein crystallography.
yes it will precipitate DNA if your lysing nuclei; add benzamidine hydrochloride though as a protease inhibitor.
The story of amidines and metal amidinate began in 1973, when A.R. Sanger first reported the discovery of N,N,N' - tris(trimethylsilyl)benzamidine in his article - Inorg Nucl Chem Lett, 1973, Issue 9, page 351. With the discovery of this versatile and powerful non-cyclopentadienyl anionic ligand, numerous amidines and metal amidinates were then reported for various main group and transition elements, e.g. volatile mono-, bis-, tris- and tetrakis- metal amidinates have been reported for a variety of applications in homogeneous catalysis, olefin polymerization, and vapor deposition technologies. These metal amidinates are classified as organometallic compounds, and are discussed in many review articles. The very first review on metal amidinates was published by K. Dehinicke in 1990 - Chem. Zeit., issue 114, page 295. The metal amidinates were probably discovered sometime after 1973 and before 1990, making their chemistry and applications as fresh as about two decades young.