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Preparation and Reactions of Sulfides

Preparation and Reactions of Sulfides

Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.

Structure and Nomenclature of Thiols and Sulfides

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Thiols and sulfides are sulfur analogs of alcohols and ethers, respectively, where the sulfur atom takes the place of the oxygen atom. Thus, thiols are generally represented as RSH, where R is an alkyl substituent and —SH is the functional group. On the other hand, in sulfides, the central sulfur atom is bonded to two hydrocarbon groups on either side. Depending upon the type of group, sulfides can be either symmetrical or asymmetrical. Both thiols and sulfides display a bent geometry, similar...

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Sulfation and α-amino acid conjugation are two critical biotransformation reactions in drug metabolism. Sulfation, a phase II biotransformation reaction, involves adding a polar sulfate group to a drug, enhancing its water solubility and promoting excretion. This process can either co-occur with or occur independently of glucuronidation. Nonmicrosomal sulfotransferase enzymes catalyze the process. The reaction involves 3'-phosphoadenosine-5'-phosphosulfate or PAPS coenzyme activation, sulfur...

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Related Experiment Video

Updated: May 31, 2026

Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability

Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability

Published on: April 2, 2015

How pH and sulfation shape human heparanase structure, stability, and substrate recognition.

Angela Pennacchio¹, Yesid Aristizabal², José Oñate-Garzón²

¹Istituto di Scienze dell'Alimentazione, CNR, Avellino, 83100, Italy.

Archives of Biochemistry and Biophysics

|May 28, 2026

Summary

Human heparanase (HPSE) activity, crucial for inflammation and metastasis, is enhanced in acidic conditions and with highly sulfated substrates. This study reveals how pH and substrate structure stabilize HPSE, impacting its physiopathological roles.

Keywords:

Heparan sulfate (HS)Human heparanase (HPSE)Molecular dynamics simulations Spectroscopic analysis (FTIR, fluorescence)pH-dependent thermostability

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Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability

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Published on: April 2, 2015

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Utilizing Thermal Shift Assay to Probe Substrate Binding to Selenoprotein O

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Published on: August 9, 2024

Area of Science:

Biochemistry
Structural Biology
Biophysics

Background:

Human heparanase (HPSE) is an enzyme degrading heparan sulfate, implicated in inflammation, metastasis, and matrix remodeling.
HPSE activity is sensitive to pH and substrate sulfation, but structural details are unclear.

Purpose of the Study:

Investigate HPSE secondary structure, stability, and substrate recognition under varying physicochemical conditions.
Elucidate the structural basis for pH and substrate sulfation effects on HPSE.

Main Methods:

Fourier-transform infrared (FTIR) spectroscopy to analyze secondary structure.
Temperature-dependent intrinsic fluorescence to assess protein stability.
Molecular dynamics (MD) simulations to model HPSE-heparan sulfate interactions.

Main Results:

FTIR showed acidic pH induces a compact, α-helix-rich HPSE conformation.
Fluorescence revealed maximal HPSE stability at pH 5.0.
MD simulations demonstrated strong ionic and hydrogen-bond interactions, with higher stability for highly sulfated heparan sulfate ligands.

Conclusions:

Acidic pH and high substrate sulfation enhance HPSE structural stability and ligand binding.
These physicochemical factors are key regulators of HPSE activity in physiopathological processes.