The synthesis of poly(gamma-stearyl L-glutamate) is reported, starting from glutamic acid. The gamma-stearyl L-glutamate amino acid (SLGAA) was prepared from stearyl alcohol and L-glutamic acid. Ring closure of SLGAA to the cyclic N-carboxyanhydride (NCA) monomer was accomplished using bis-(trichloromethyl) carbonate (triphosgene). Polymerization of the SLGNCA monomer in the presence of either primary amines or sodium methoxide produced a series of polypeptides with molecular weights ranging from 20 000 to 300 000. The polydisperse polymers were characterized by static and dynamic light scattering, solution viscometry, H-1 and C-13 NMR, and infrared spectroscopy. The polymer was also modeled using the SYBYL molecular graphics package. The combined data indicate a semiflexible structure, with PSLG side chains being well extended from the polymer backbone in the good solvent, tetrahydrofuran. Gel permeation chromatography and dynamic light scattering data indicated polydispersity ratios (M(w)/M(n)) in the range of 1.1-2.0. The Mark-Houwink-Sakurada coefficients obtained were K = (1.26 +/- 0.3) x 10(-5) cm(3)/g and a = 1.29 +/- 0.09 for M(w) in the range of 38 000-250 000. The hydrodynamic diameter of the PSLG rod was calculated to be 3.7 +/- 0.2 nm; the diameter of mutual exclusion calculated from the Zimm-Schulz-Onsager equation was 3.6 +/- 0.7 nm. These values were in good agreement with the value obtained from the SYBYL molecular model.