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Medical Term:


Pronunciation: ti'ro-thri'sin

Definition: An antibacterial mixture obtained from peptone cultures of Bacillus brevis; bactericidal and bacteriostatic, and active against gram-positive bacteria. It yields the crystalline antibacterial agents gramicidin and tyrocidin; the gramicidin component is a polypeptide containing l-tryptophan, d-leucine, d-valine, l-valine, l-alanine, glycine, and an aminoethanol; the tyrocidin component is a cyclopolypeptide containing tyrosine, ornithine, and several other amino acids.

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