Do you know what chemical causes rotten eggs to smell so bad? In this lesson, we will discover what a sulfhydryl group is. We’ll also learn more about its structure and properties.
What Is a Sulfhydryl Group?
If you’ve ever been unlucky enough to be sprayed by a skunk, you know just how stinky a sulfhydryl group can be.
Chemists who had the unfortunate task of analyzing this chemical defense mechanism identified thiols, or compounds that contain the sulfhydryl group, as one of its components. Let’s learn more about the sulfhydryl group, beginning with its basic structure.The sulfhydryl group is a family of organic compounds that contains an R group bound to a sulfur atom and a hydrogen atom. An R group is a side chain that has a carbon or hydrogen atom attached to the rest of a molecule. Differences in R groups increase the diversity of the sulfhydryl compounds that can be created.
Sulfhydryl groups belong to a family called organosulfur compounds. Organosulfur compounds are those substances whose structures include a sulfur atom.
Sulfhydryl Group Structure
The molecular formula for a sulfhydryl group is R-SH, which is similar to another functional group: alcohols (R-OH). The only difference between these groups is the presence of a sulfur atom versus an oxygen atom. Remember that a sulfhydryl group belongs to the family of organosulfur compounds. Now that we know what a sulfhydryl group structure looks like, can you spot one in the following examples of organosulfur compounds? Remember to focus on locating the sulfur atom bonded to a hydrogen atom, which is a major indication that a sulfhydryl group is present. Anything attached to the sulfur atom is the R group.
Sulfhydryl Group – Properties ; Sources
We’ve already confirmed that a sulfhydryl group can be one stinky compound. Its odor ranges from that of rotten eggs to garlic. Sulfhydryl groups are slightly polar and show moderate interest in forming hydrogen bonds with other molecules. Because of their slight polarity, they have a low boiling point. The more polar a compound, the higher its boiling point. They are less soluble in polar substances, like water.
Where might a sulfhydryl group be found? When part of different organosulfur compounds, sulfhydryl is found in a variety of places. For example, when you roast coffee beans, the thiol seen below provides that coffee smell. As you can see, a sulfhydryl group is present in the structure of the molecule.
This is actually quite nice to learn because it means that sulfhydryl groups don’t smell bad all the time!
Sulfhydrl groups also can be found in wine, though this usually isn’t a good thing. If yeast interacts with sulfur during the wine-making process, the result is a compound which contains a sulfhydryl group and gives wine a nasty odor similar to skunk spray.
Other places where sulfhydryl groups can be found include gasoline and the amino acid cysteine, which plays an important role in facilitating hair growth. As you can see, in terms of its molecular formula, sulfhydryl groups are pretty useful in both chemical and biological applications.
The sulfhydryl group belongs to a family of organosulfur compounds. This group contains a sulfur atom bonded to a hydrogen atom and an R group. The molecular formula for sulfhydryl is R-SH.
Sulfhydryl groups often have a strong, offensive odor. Other physical properties include a low boiling point and moderate polarity. The sulfhydryl group is biologically important given its presence in the amino acid cysteine, which contributes to hair growth.