How bleach defeats green slime

Reuters:

Bleach has been killing germs for more than 200 years but U.S. scientists have just figured out how the cleaner does its dirty work.

It seems that hypochlorous acid, the active ingredient in bleach, attacks proteins in bacteria, causing them to clump up much like an egg that has been boiled, a team at the University of Michigan reported in the journal Cell on Thursday.

The discovery, which may better explain how humans fight off infections, came quite by accident.

"As so often happens in science, we did not set out to address this question," Ursula Jakob, who led the team, said in a statement.

The researchers had been studying a bacterial protein called heat shock protein 33, which is a kind of molecular chaperon that becomes active when cells are in distress, for example from the high temperature of a fever.

In this case, the source of the distress was hypochlorous acid or hypochlorite.

Jakob's team figured out that bleach and high temperatures have very similar effects on proteins.

When they exposed the bacteria to bleach, the heat shock protein became active in an attempt to protect other proteins in the bacteria from losing their chemical structure, forming clumps that would eventually die off.

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This part of Texas tends to have a humid climate that leads to the growth of green grunge particularly on the north side of the house. Mixing bleach with detergent and brushing it on the siding works better than a pressure washer in cleaning the house and does not do as much damage. I found that it also works on stains on dishes too.