The present invention relates to antimicrobial peptides comprised of a first domain with activity specific to a peptidoglycan or component thereof; a second domain with activity specific to an ester linkage; and a third domain with membrane permeabilising activity. The invention also relates to the use of such peptides in medicine, for example for treating mycobacterial infection.

A reagent composition for use as a first reagent composition in a method of quantifying a small dense LDL cholesterol (sdLDL-C) in a sample, the method including causing the first reagent composition to react to the sample, and after the causing the first reagent composition to react to the sample, causing a second reagent composition for quantifying the sdLDL-C to react, thereby quantifying cholesterol in a remaining lipoprotein, the reagent composition includes a nonionic surfactant and has cholesterol esterase activity, cholesterol oxidase activity, and sphingomyelinase activity, and a contact angle between the reagent composition and a polyethylene terephthalate (PET) base material is equal to or more than 63.0 and equal to or less than 67.0.