title: Metabolic stability of glutaraldehyde cross-linked peptide DNA condensates.
abstract: The stability of peptide DNA condensates was examined after introducing glutaraldehyde to cross-link surface amine groups. A 20 amino acid peptide (CWK(18)) was used to condense DNA into small (70 nm) condensates. The reaction between glutaraldehyde and peptide DNA condensates was indirectly monitored using a fluorescence-based assay to establish reaction completion in 4-5 h when using glutaraldehyde-to-peptide ratios of 1 to 4 mol equiv. Higher levels of glutaraldehyde cross-linking led to significant increases in particle size. The improved stability imparted by glutaraldehyde cross-linking was demonstrated by the increased resistance of DNA condensates to shear stress induced fragmentation. The cross-linked condensates were also significantly more resistant to in vitro metabolism by serum endonucleases. A decrease in the magnitude of transient gene expression was determined for cross-linked DNA condensates which also resulted in a 10-day steady-state expression when cross-linking with 4 mol equiv of glutaraldehyde. The results suggest that cross-linking DNA condensates may provide a means to alter the time course of transient gene expression by inhibiting DNA metabolism.
authors.affiliation: Divisions of Pharmaceutics and Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109-1065, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Adami
authors.forename: K G
authors.initials: KG
authors.lastname: Rice
mesh_terms: D002738:Chloroquine / Q000494:pharmacology; D003432:Cross-Linking Reagents; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D053938:DNA Fragmentation; D004355:Drug Stability; D004720:Endonucleases / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D018014:Gene Transfer Techniques; D005976:Glutaral / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008074:Lipoproteins / Q000096:biosynthesis / Q000235:genetics; D010316:Particle Size; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011107:Polylysine / Q000096:biosynthesis / Q000235:genetics; D013050:Spectrometry, Fluorescence
chemical_list: D003432:Cross-Linking Reagents; D008074:Lipoproteins; D010455:Peptides; C051928:lipoprotein-associated coagulation inhibitor; D011107:Polylysine; D002738:Chloroquine; D004247:DNA; D004720:Endonucleases; D005976:Glutaral