Endonuclease
1. An enzyme that breaks strands of D A. at internal positions; these enzymes are important tools in recombinant DNA technology. See nuclease.
2. An enzyme which digests nucleic acids starting in the middle of the strand (as opposed to. an exonuclease, which must start at an end). Examples include the restriction enzymes, DNase I and RNase A

Endapolyploidy
The result of nuclear divisions without subsequent cytoplasmic division (cytokinesis); the polyploids so obtained are called endopolyploids. See polyploidy.

Endoprotease
An enzyme that cleaves the peptide bonds between amino acids within a protein. Cleavage is usually at one or more specific sites.
Endoreduplication
Chromosome reproduction during interphase. 4-chramatid chromosomes (diplochromosomes) are seen during this phase.

Endotoxin
A component of the cell wall of Gram-negative bacteria that elicits, in mammals, an inflammatory response and fever. end-product inhibition The inhibition of an enzyme by a metabolite: The enzyme is sometimes the first enzyme in a biosynthetic pathway, and the metabolite is generally the product of the last step in the pathway. See feedback inhibition. enhancer 1. A substance or object that increases a chemical activity or a physiological process. 2. A DNA sequence that increases the transcription of a eukaryotic gene when they are both on the same DNA molecule. a.k.a. enhancer element; enhancer sequence.

Engineering ceramics
Technical ceramics for structural applications.