scholarly journals Intracellular Delivery of Antisense DNA and siRNA with Amino Groups Masked with Disulfide Units

2020 ◽  
Vol 68 (2) ◽  
pp. 129-132 ◽  
Author(s):  
Zhaoma Shu ◽  
Azumi Ota ◽  
Yukiya Takayama ◽  
Yuri Katsurada ◽  
Kosuke Kusamori ◽  
...  
Keyword(s):  
Intracellular Delivery ◽  
Amino Groups ◽  
Antisense Dna

Aldehyde gold clusters for molecular labeling

1995 ◽  
Vol 53 ◽  
pp. 858-859
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya
Keyword(s):  
Covalent Bond ◽  
Aldehyde Group ◽  
Gold Clusters ◽  
Side Reactions ◽  
Amino Groups ◽  
Sodium Cyanoborohydride ◽  
Schiff’S Base ◽  
Protein Molecules ◽  
Hydroxysuccinimide Esters ◽  
Primary Amino

Glutaraldehyde is a useful tissue and molecular fixing reagents. The aldehyde moiety reacts mainly with primary amino groups to form a Schiff's base, which is reversible but reasonably stable at pH 7; a stable covalent bond may be formed by reduction with, e.g., sodium cyanoborohydride (Fig. 1). The bifunctional glutaraldehyde, (CHO-(CH2)3-CHO), successfully stabilizes protein molecules due to generally plentiful amines on their surface; bovine serum albumin has 60; 59 lysines + 1 α-amino. With some enzymes, catalytic activity after fixing is preserved; with respect to antigens, glutaraldehyde treatment can compromise their recognition by antibodies in some cases. Complicating the chemistry somewhat are the reported side reactions, where glutaraldehyde reacts with other amino acid side chains, cysteine, histidine, and tyrosine. It has also been reported that glutaraldehyde can polymerize in aqueous solution. Newer crosslinkers have been found that are more specific for the amino group, such as the N-hydroxysuccinimide esters, and are commonly preferred for forming conjugates. However, most of these linkers hydrolyze in solution, so that the activity is lost over several hours, whereas the aldehyde group is stable in solution, and may have an advantage of overall efficiency.

The Action of Thrombin on Modified Fibrinogen

1983 ◽  
Vol 49 (03) ◽  
pp. 208-213
Author(s):  
A J Osbahr
Keyword(s):  
Physical Properties ◽  
Negative Charge ◽  
Lysine Residue ◽  
Fibrinopeptide A ◽  
Amino Groups ◽  
Lysine Residues ◽  
Citraconic Anhydride

SummaryThe modification of canine fibrinogen with citraconic anhydride modified the ε-amino groups of the fibrinogen and at the same time generated additional negative charges into the protein. The addition of thrombin to the modified fibrinogen did not induce polymerization; however, the fibrinopeptide was released at a faster rate than from the unmodified fibrinogen. The physical properties of the citraconylated fibrinogen were markedly altered by the modification of 50-60 lysine residues in one hour. A modified fibrinopeptide-A was released by thrombin from the modified fibrinogen and was electrophoretically more anionic than the unmodified fibrinopeptide-A. Edman analysis confirmed the modification of the lysine residue present in the peptide. The rate of removal of citraconylated fibrinopeptide-A from modified fibrinogen by thrombin was 30 to 40 percent greater than the cleavage of unmodified fibrinopeptide-A from unmodified fibrinogen. However, the modification of 60 or more lysine residues in the fibrinogen produced a decrease in the rate of cleavage of citraconylated fibrinopeptide-A. The results suggest that additional negative charge in the vicinity of the attachment of fibrinopeptide-A to canine fibrinogen aids in the removal of the peptide by thrombin.

COMPARATIVE STUDIES OF THE POTENTIATION OF CORTICOTROPHIN ACTIVITY BY SEVERAL INACTIVE DERIVATIVES

1963 ◽  
Vol 42 (2) ◽  
pp. 209-213 ◽  
Author(s):  
Arthur I. Cohen ◽  
Edward H. Frieden
Keyword(s):  
Biological Activity ◽  
Comparative Studies ◽  
Free Amino ◽  
Hormonal Activity ◽  
Amino Groups

ABSTRACT A number of corticotrophin analogues have been prepared, some of which potentiate the biological activity of the untreated hormone in vitro. The free amino groups of corticotrophin appear to be essential not only for hormonal activity, but also for the interaction of the analogues with the tissue corticotrophin inactivating system which is assumed to account for the potentiating effect.

Probing Cellular Outcomes Using Heterobivalent Constructs

2019 ◽  
Author(s):  
Rohit Bhadoria ◽  
Kefeng Ping ◽  
Christer Lohk ◽  
Ivar Järving ◽  
Pavel Starkov
Keyword(s):  
Cell Viability ◽  
Small Molecules ◽  
Cellular Uptake ◽  
Kinase Inhibitors ◽  
Rho Kinase ◽  
Intracellular Delivery ◽  
Rho Kinase Inhibitors

<div> <div> <div> <p>Conjugation techniques are central to improving intracellular delivery of bioactive small molecules. However, tracking and assessing the overall biological outcome of these constructs remains poorly understood. We addressed this issue by having developed a focused library of heterobivalent constructs based on Rho kinase inhibitors to probe various scenarios. By comparing induction of a phenotype of interest vs. cell viability vs. cellular uptake, we demonstrate that such conjugates indeed lead to divergent cellular outcomes. </p> </div> </div> </div>

Biphenyl-Derivatives Possessing Tertiary Amino Groups as β-Secretase (BACE1) Inhibitors

2010 ◽  
Vol 7 (7) ◽  
pp. 507-515
Author(s):  
Simone Bertini ◽  
Elisa Ghilardi ◽  
Valentina Asso ◽  
Carlotta Granchi ◽  
Filippo Minutolo ◽  
...  
Keyword(s):  
Amino Groups ◽  
Tertiary Amino

Intracellular Delivery of Nanocarriers for Cancer Therapy

2007 ◽  
Vol 3 (4) ◽  
pp. 329-338 ◽  
Author(s):  
Yah-el Har-el ◽  
Yoshinori Kato
Keyword(s):  
Cancer Therapy ◽  
Intracellular Delivery

Chitosan Nanoparticles: An Approbative System for the Delivery of Herbal Bioactives

2020 ◽  
Vol 10 ◽  
Author(s):  
Sapna Saini ◽  
Sanju Nanda ◽  
Anju Dhiman
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
State Of The Art ◽  
Chitosan Nanoparticles ◽  
Delivery Systems ◽  
Intrinsic Properties ◽  
Amino Groups ◽  
Suitable Candidate ◽  
Film Forming ◽  
Novel Drug

: Chitosan, a natural biodegradable polymer obtained from deacetylation of chitin, has been used as an approbative macromolecule for the development of various novel drug delivery systems. It is one of the most favorable biodegradable carriers for nanoparticulate drug delivery due to its intrinsic properties, such as biocompatibility, biodegradability, non-toxicity, availability of free reactive amino groups, and ease of chemical modification into different active derivatives. Furthermore, interesting physical properties (film-forming, gelling and thickening) make it a suitable candidate for formulations, such as films, microcapsules, beads, nanoparticles, nanofibres, nanogel and so on. Researchers have reported that chitosan nanoparticles act as a promising vehicle for herbal actives as they provide a superior alternative to traditional carriers and improve pharmaceutical efficiency. As no review of chitosan nanoparticles encapsulating herbal extracts and bioactives has been published till date, a maiden effort has been made to collate and review the use of chitosan nanoparticles for the entrapment of phytoconstituents to yield stable, efficient and safe drug delivery systems. Additionally, the paper presents a comprehensive account of the state-of the-art in fabricating herbal chitosan nanoparticles and their current pharmacological status. A list of patents on chitosan nanoparticles of herbal actives has also been included. This review is intended to serve as a didactic discourse for the formulation scientists endeavoring to develop advanced delivery systems for herbal actives.

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