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The adjacent image is a Spartan ELPOT surface of the Penicillin molecule. The coloring indicates sites of electron density. Blue areas are characterized by a low electron density and red areas mark high electron density. Thus, the red areas are more negative in charge while the blue areas are less negative. Penicillinase associates with Penicillin and adds a water molecule to the bond between the nitrogen and the carbon of the carbonyl group in the Beta-Lactam ring. The water molecule performs a nucleophilic attack on the carbonyl carbon, creating a tetrahedral intermediate state in which the oxygen of the water molecule is partially bound to the carbon and one of the hydrogens from the water molecule is partially bound to the nitrogen in the Beta-lactam ring. The bond between carbon and nitrogen breaks as does the bond between oxygen and hydrogen. Simultaneously the bond between carbon and and oxygen forms as does the bond between nitrogen and hydrogen. The Beta-Lactam ring is destroyed, and the Penicillin molecule inactivated.