A Rose by Any Other Name (or Enzyme) Would Smell as Sweet (or Sweeter!)

By Jim Schmidt
Sr. Scientific Advisor
ABC Laboratories
www.abclabs.com

Summer is here - and while every season has its own pleasures, perhaps no time of the year treats all of our senses as well as the summer months do…and behind those sights, smells, sounds, textures, and tastes is some interesting chemistry (and even some new discoveries)!

Stop and smell the roses - as the advice goes - and you'll get a whiff of...geraniol.  Hundreds of individual compounds, in varying amounts, constitute rose oil, but geraniol - a monoterpenoid alcohol - is a significant contributor to the plant's signature scent (and contributes to the scent of other oils as well, such as geranium and lemon).

A report in the esteemed journal, Science, published just over two weeks ago, sheds new light on how the plant manufactures the chemical.  In most plants, the enzyme "geraniol synthase" converts the precursor, geranyl diphosphate, to geraniol. Using genetic mapping, the researchers found that highly-scented roses expressed a particular gene (RhNUDX1) at higher levels than less fragrant plants.  The gene codes an enzyme that facilitates the biosynthesis of geraniol. It turns out that roses are often bred more for color or longevity, rather than scent.  By using the “Nudix” gene as a biomarker, breeders may be able to cultivate more fragrant roses for us to stop and smell.

Few places in the home offer more lessons in chemistry than the kitchen.  During the summer, the kitchen often moves to the outdoors – especially at the grill – which produces some interesting chemistry as well!  One of my favorite parts of reading Chemical & Engineering News each week is the regular “PeriodicGraphics” feature, a collaborative effort with Andy Brunning, author of the popular Compound Interest blog.  A recent installment described the “Chemistry of Barbecue,” with explanations of the compounds that contribute to the smoky aroma and taste of charcoal and the Maillard Reaction that is responsible for the delicious flavors and colors of barbecued meats.

Add in the pleasant sight of the bioluminescence of fireflies in the evening or the less-than-pleasant venom of a stinging insect, and you can see that summer presents a wonderful (if sometimes painful) laboratory.

Enjoy the season – and the interesting chemistry that attends to it - until the "last rose of summer."

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