Definition

Noun: 1. A polypeptide antibiotic: A basic (alkaline) polypeptide antibiotic substance that is derived from the soil bacterium Bacillus brevis. It is one of the two major active components, along with gramicidin, that together constitute the antibiotic mixture known as tyrothricin.

Usage

• Tyrocidine is effective primarily against Gram-positive bacteria.
• Due to its toxicity to human cells, tyrocidine is not used systemically (inside the body) but has historical and limited topical use (on the skin or mucous membranes).

Examples

• The antibiotic tyrocidine was isolated from the bacterial culture.
• Early research showed that tyrocidine disrupts bacterial cell membranes.
• Tyrocidine's hemolytic activity limits its medicinal applications.

Advanced Usage

• Scientific Context: In biochemistry and microbiology, "tyrocidine" refers specifically to a family of cyclic decapeptides (molecules composed of ten amino acids in a ring structure). Different variants (e.g., tyrocidine A, B, C) have slightly different amino acid compositions.

Variants and Related Words

• Tyrothricin (noun): The broader antibiotic complex isolated from , which is a mixture of approximately 20% gramicidin and 80% tyrocidine.
• Gramicidin (noun): The other major polypeptide antibiotic component of tyrothricin, which is often contrasted with tyrocidine in scientific literature.

Synonyms

• Polypeptide antibiotic
• Cyclic decapeptide antibiotic

Notes on Meaning

• The term is highly specific to the fields of microbiology, antibiotic discovery, and biochemistry. It is not a common word in general English usage.
• Its meaning is intrinsically linked to its source (), its chemical structure (polypeptide), and its partner compound in tyrothricin (gramicidin).

Noun

1. a basic polypeptide antibiotic derived from a soil bacterium; a major component of tyrothricin