A study of enzymic degradation of a macromolecular substrate, , by gel permeation chromatography and kinetic modelling

Pytela, Jindřich; Jakeš, J.; Rypáček, František

doi:10.1016/0141-8130(94)90005-1

Cited by 16 publications

(8 citation statements)

References 18 publications

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“…48 Degradation of poly(HEGln) by papain was investigated before this study. 37,[49][50][51] Dickinson and coworkers reported that the degradation of poly(HEGln) by papain generated products ranging from tetrapeptides to nonapeptides. 37,51 Yaacobi et al proposed that the degradation followed a modified MichaelisMenten model and suggested that the reaction stopped when the degradation fragments were tetrapeptides.…”

Section: Discussionmentioning

confidence: 98%

Lysosomal degradability of poly(?-amino acids)

Chiu

Kopečková

Deshmane

et al. 1997

J. Biomed. Mater. Res.

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The lysosomal degradability of poly(alpha-amino acids) based on poly(L-glutamic acid) and its derivatives/copolymers was evaluated to gain insight into the subcellular fate of the macromolecules as water soluble polymeric drug carriers. The results indicate that both the incorporation of hydrophobic comonomers and modification of the carboxylic groups of glutamic acid side chains with hydroxyalkylamine increase the lysosomal degradability of the copolymers. Decreased lysosomal degradability of L-glutamic acid copolymers containing tripeptides terminated in p-nitroanilide (drug model) in the side chains confirmed that drug conjugation alters the degradation pattern of the polymeric carriers. The percentages of the enzymatic release of p-nitroaniline from its polymeric complex with time is relatively independent of the contents of the tripeptidyl p-nitroanilides attached to the polymeric conjugates. Determination of the degradation products by electrospray mass spectroscopy showed that no fragments less than 10(3) D were generated by lysosomal enzymes, whereas the main degradation products by papain and chymotrypsin were tripeptides and tetrapeptides. The conclusions derived from these data strongly suggest that these macromolecules, if used as lysosomotropic drug carriers, may accumulate in the lysosomes and limit their usefulness in some applications.

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Section: Discussionmentioning

confidence: 98%

Lysosomal degradability of poly(?-amino acids)

Chiu

Kopečková

Deshmane

et al. 1997

J. Biomed. Mater. Res.

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“…Experimentally, the development of gel permeation chromatography (GPC) to measure the MWD has proved to be an important technique for investigating polymer degradation. By combining these analytical and experimental methods, significant insights into the kinetics and mechanisms of polymer degradation have been realized for systems such as acid hydrolysis of dextran, 6 enzymatic degradation of polyglutamine, 7,8 ultrasonication of nucleic acids, 9 and degradation of polystyrene. 10 In this paper, we present our initial findings on the mechanisms of degradation of guar galactomannan and the concomitant changes in viscosity.…”

Section: Introductionmentioning

confidence: 99%

Degradation of a Water-Soluble Polymer: Molecular Weight Changes and Chain Scission Characteristics

2000

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Computer simulations in conjunction with molecular weight distributions, obtained from gel permeation chromatography (GPC), are used to obtain physical insights on the mechanisms of degradation of guar galactomannan, a naturally occuring polysaccharide. Two different modes of degradation, sonication and enzymatic hydrolysis, are compared. Both modes of guar degradation reveal similar features in terms of changes in molecular weights, a rapid reduction followed by a slow decrease. However, the molecular weight distributions are significantly different, with ultrasonication leading to a narrowing of the molecular weight distribution and enzymatic hydrolysis resulting in its broadening. Sonication of guar results in a random degradation of chains, so that all bonds have equal probability of cleavage. In contrast, enzymatic degradation does not follow any of the typical modes of chain scission (random, Gaussian, and central), indicating that enzymatic hydrolysis of guar does not obey a "single scission" pathway. Plots of the zero shear viscosity, η o, as a function of number-average molecular weight, Mn, show enzymatically degraded guar to possess a much higher viscosity compared to a sonicated guar, at the same Mn. This contrasts the behavior of zero shear viscosity, ηo, vs weight-average molecular weight, Mw, where both systems are identical despite the large differences in polydispersity. We infer that, for polydisperse systems, the steady shear rheological properties are not very sensitive to the entire molecular weight distribution and can be adequately described by Mw, the molecular weight average that is primarily controlled by the high molecular weight fraction.

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“…Fortunately, the average molecular weight of EZLA is very close to that determined by 1 H NMR, and the results are exhibited in Table 2. However, in order to gain the primary amine on the lysine side chain, the copolymer EZLA was then treated with a 33% solution of HBr in HAc to remove the benzyloxycarbonyl protective group in the side chain by acidolysis [63] and yield ELA with free amino group. During the deprotection reaction, trifluoroacetic acid was first added to dissolve the copolymer of EZLA, which was cooled in an ice bath.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of biodegradable amphiphilic triblock copolymers methoxy-poly(ethylene glycol)-b-poly(L-lysine)-b-poly(L-lactic acid)

Zhu

Yang

et al. 2012

J Polym Res

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Starting from MPEG-NH 2 , a series of amphiphilic triblock copolymers MPEG-b-PLL-b-PLA were synthesized through PEG-NH 2 -initiated ring-open polymerization of N ε-benzyloxycarbonyl-L-lysine, followed by acylation coupling between the amino-terminated MPEG-b-PZLL-NH 2 and carboxyl-terminal PLA and the deprotection of amines. The block copolymers were characterized by FT-IR, 1 H NMR, GPC, DSC and TEM. The copolymer functional groups, molecular and block structures were verified by FT-IR, 1 H NMR and DSC, respectively. The GPC results indicate that the chain lengths of each block can be controlled by varying the feed ratios of the monomer and initiator, providing the polymer samples with a narrow molecular weight distribution (M w /M n 01.10~1.25). The TEM analysis shows that the triblock polymers can self-assemble into polymeric micelles in aqueous solution with spherical morphology. The cellcytotoxicity assay indicates that the triblock polymers show no obvious cytotoxicity against Bel7402 human hepatoma cells.

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A study of enzymic degradation of a macromolecular substrate, , by gel permeation chromatography and kinetic modelling

Cited by 16 publications

References 18 publications

Lysosomal degradability of poly(?-amino acids)

Lysosomal degradability of poly(?-amino acids)

Degradation of a Water-Soluble Polymer: Molecular Weight Changes and Chain Scission Characteristics

Synthesis and characterization of biodegradable amphiphilic triblock copolymers methoxy-poly(ethylene glycol)-b-poly(L-lysine)-b-poly(L-lactic acid)

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