defensinn.
/dᵻˈfɛnsn/, U.S. /dəˈfɛns(ə)n/, /diˈfɛns(ə)n/ Biochemistry.
Any of a family of small peptides with antibiotic activity, found in both animals and plants.Defensins, which are divided on the basis of their structure into two main subfamilies designated alpha and beta, contain six cysteine residues linked by disulphide bonds, and are capable of binding to and altering the permeability of microbial membranes.
ΚΠ
1985 M. E. Selsted et al. in Jrnl. Clin. Investig. 76 1436/1 The peptides, HNP-1, HNP-2, and HNP-3, which we have termed defensins, were rich in cystine, arginine, and aromatic residues, but were devoid of free sulfhydryl groups and carbohydrate moieties.
1990 EMBO Jrnl. 9 2507 Insect defensins show significant homologies to mammalian (including human) microbicidal peptides present in polymorphonuclear leukocytes and macrophages.
1998 N.Y. Times 23 Aug. 36 Biosource is experimenting with making a dozen or so varieties of ‘defensins’ in tobacco.
2002 Time 7 Oct. 108/4 Using new protein-chip technology, they have identified three proteins—alpha-defensins 1, 2, and 3—that are present in nonprogressors but not in AIDS patients.
2009 J. C. Knight Human Genetic Diversity iv. 121/2 β defensins are small secreted antimicrobial peptides with cytokine-like properties which are found expressed at high levels in psoriatic plaques.
This entry has been updated (OED Third Edition, December 2016; most recently modified version published online March 2022).
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n.1985