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共 58 篇文章
On-Resin Disulfide Formation in Peptide SPPS
On-resin disulfide formation builds a cysteine-cysteine bond while the peptide remains attached to a solid-phase synthesis resin. For CHEMOS readers, the practical question is whether this placement can simplify workup and control intramolecular cyclization without creating new impurity risks. The process variables are linked: oxidant choice, protecting groups, resin swelling, solvent salts, reaction time, and TFA scavenger composition can all affect the final crude peptide profile.
GalNAc-siRNA ADME: Uptake, Metabolism, and DDI Lessons
For oligonucleotides, the familiar small-molecule ADME checklist is useful as a list of questions, not as a mechanistic shortcut. These molecules are large, highly charged nucleic acid polymers that rely on non-oral delivery, uptake pathways, and nuclease-driven metabolism. For CHEMOS readers, the chemistry translation is direct: GalNAc building blocks, linker behavior, backbone modification, nuclease stability, and LC-MS method design all affect what downstream ADME data can mean.
Glycan-Directed ADC Conjugation: Donor Design and DAR Control
OBI Pharma's WO2026117757 describes a method for building site-specific antibody-drug conjugates through the conserved N297 glycan region of an antibody. The workflow trims native N-glycans to a core GlcNAc acceptor, installs functionalized sugar donors, and then couples linker-payload units by bioorthogonal chemistry. CHEMOS readers should care because the disclosure frames DAR as a glycan-donor design variable, not only as an outcome of stochastic lysine or cysteine conjugation.
Site-Specific ADC Conjugation: Chemistry Choices for DAR Control
Site-specific ADC conjugation attaches payloads at defined antibody locations instead of relying on broadly reactive lysine or reduced disulfide chemistry. Site-specific ADC strategies include engineered cysteine, unnatural amino acid, and enzymatic routes as three major ways to control drug-to-antibody ratio (DAR), commonly around 2 or 4. For CHEMOS readers, the practical issue is not only biological design but linker-payload compatibility, hydrophobicity management, reaction sequence, and LC-MS confirmation.
5'-VP Makes GalNAc-siRNA 5'-End Control a Screening Question
5'-(E)-vinylphosphonate, or 5'-VP, is a phosphate mimic placed at the 5' end of an siRNA antisense strand. In the primary ChemBioChem paper cited by the source, the reported response depended on whether a sequence was phosphate-dependent, rather than on GalNAc delivery alone. The practical question for oligonucleotide teams is when to compare 5'-OH, 5'-P, and 5'-VP versions, then track intact strand, terminal identity, total siRNA exposure, and Ago2-associated material where those assays are available.
Antibody-Drug Conjugate Design and Mechanism of Action: Antibody, Linker and Payload
An antibody-drug conjugate (ADC) combines biological targeting with small-molecule potency. The antibody is designed to recognize a tumor-associated antigen. The payload provides the cell-killing or cell-modulating activity. The linker connects the two and controls how stable the conjugate is in circulation and how the payload is released after the ADC reaches the target cell. That simple description hides a complex development problem. ADC performance depends on antigen biology, antibody selection, linker design, payload properties, conjugation site, drug-to-antibody ratio (DAR), formulation and analytical control. A strong ADC program therefore needs coordinated biology and chemistry rather than a payload simply attached to an antibody.