Synthesis and Some Solution Properties of Poly(.gamma.-stearyl .alpha.,L-glutamate)

Abstract

The synthesis of poly(y-stearyl L-glutamate) is reported, starting from glutamic acid. The y-stearyl L-glutamate amino acid (SLGAA) was prepared from stearyl alcohol and L-glutamic acid. Ring closure of SLGAA to the cyclic -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, and 13C 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 (MJMn) in the range of 1.1-2.0. The Mark-Houwink-Sakurada coefficients obtained were K = (1.26 ± 0.3) x 10-5 cm3/g and a = 1.29 ± 0.09 for Mw 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.

Effects of age on nerve fibers in the rhesus monkey optic nerve

“…In particular, polymers constituted by either α‐ or β‐amino acids with attached flexible side chains have received a special attention 11–18. The most representative members of these families of comb‐like polymers are the poly(γ‐alkyl‐α‐L‐glutamate)s11–15 and the poly(α‐alkyl‐β‐L‐aspartate)s 16–18. These consist of peptide α‐like‐helices, which impart rod‐like character to the macromolecules, coupled with long aliphatic side chains emerging from the repeat units.…”

Surface characteristics of poly(γ‐alkyl α l‐glutamate)s with different alkyl groups

“…As shown in Scheme 1, PELG, POLG, PDLG, and PSLG were synthesized by the ring-opening polymerization of corresponding NCAs, which is the most economical and expedient process to get synthetic polyglutamates with high molecular weight. [21][22][23][24]28 These polyglutamates differ only in the side alkyl group (carbon number equals to 2, 8, 12, or 18). It is appealing to study the influence of the alkyl group on the surface characteristics of polymer with these polyglutamates as the models.…”

“…Poly(c-ethyl a L-glutamate) (PELG), poly(c-octyl a L-glutamate) (POLG), poly(c-dodecyl a L-glutamate) (PDLG), and PSLG were synthesized according to the reported procedure. [21][22][23][24] Bovine serum albumin (BSA, purity > 98%) was purchased from Sino-American Biotechnology, and Bovine fibrinogen (BFg, Type I-S, 65-85%) was obtained from Sigma-Aldrich.…”

Polymerization of γ‐stearylL‐glutamateN‐carboxyanhydride with multifunctional porphyrin initiator

“…PSLG was previously obtained by trans-esterification of commercially available poly(g-benzyla,L-glutamate) or poly(g-methyl-a,L-glutamate) with stearyl alcohol, though the reaction is definitely incomplete. Recent studies [3,4] have been devoted to synthesize high-molecular-weight PSLG by the ring-opening polymerization of g-stearyl L-glutamate N-carboxyanhydride (SLGNCA, Fig. 1a).…”

“…1a). It was found that primary amines can initiate N-carboxyanhydride (NCA) polymerization, and these initiators remain attached to the growing polypeptide chain [3]. In an attempt to construct porphyrin-containing polypeptide, it occurred to us that it should be possible to synthesize a multi-branched PSLG with porphyrin core by using multi-amino porphyrin as the initiator.…”