Bacterial cytochrome P450s form a remarkable clade of the P450 superfamily of oxidative hemoproteins, and are often involved in the biosynthesis of complex natural products. Those in a subgroup known as Oxy enzymes play a crucial role in the biosynthesis of glycopeptide antibiotics, including vancomycin and teicoplanin. The Oxy enzymes catalyze crosslinking of aromatic residues in the non-ribosomal antibiotic precursor peptide while it remains bound to the non-ribosomal peptide synthetase (NRPS); this crosslinking secures the three-dimensional structure of the glycopeptide, crucial for antibiotic activity. We have characterized OxyBtei , the first of the Oxy enzymes in teicoplanin biosynthesis. Our results reveal that OxyBtei possesses a structure similar to those of other Oxy proteins and is active in crosslinking NRPS-bound peptide substrates. However, OxyBtei displays a significantly altered activity spectrum against peptide substrates compared to its well-studied vancomycin homologue.