Perry D, Abraham E P
J Gen Microbiol. 1979 Nov;115(1):213-21. doi: 10.1099/00221287-115-1-213.
L-Alanyl-L-tyrosine and glycyl-L-phenylalanine labelled with 14C competed with each other and with the dipeptide antibiotic bacilysin for transport into Staphylococcus aureus NCTC 6571 in a medium which did not support growth. They also competed with other dipeptides and several tripeptides. The fast initial transport ofthe two labelled peptides appeared to show Michaelis-Menten kinetics. Neither was transported into a bacilysin-resistant mutant of S. aureus NCTC 6571, although tyrosine was taken up by the mutant as readily as it was by the parent strain. Uptake of alanyltyrosine or glycylphenylalanine was followed by rapid hydrolysis of the peptide and the excretion of tyrosine or phenylalanine. Glycine liberated from glycylphenylalanine was partly degraded and partly incorporated into the bacterial wall. The behaviour of these dipeptides paralleled the inactivation of bacilysin by suspensions of S. aureus and the appearance of its C-terminal amino acid, anticapsin, in the extracellular fluid.
用¹⁴C标记的L-丙氨酰-L-酪氨酸和甘氨酰-L-苯丙氨酸在不支持生长的培养基中相互竞争，并与二肽抗生素杆菌溶素竞争转运进入金黄色葡萄球菌NCTC 6571。它们还与其他二肽和几种三肽竞争。两种标记肽的快速初始转运似乎呈现米氏动力学。尽管酪氨酸被该突变体摄取的速度与亲本菌株一样快，但两种肽都不能转运进入金黄色葡萄球菌NCTC 6571的杆菌溶素抗性突变体。丙氨酰酪氨酸或甘氨酰苯丙氨酸被摄取后，肽会迅速水解，酪氨酸或苯丙氨酸会被排泄。从甘氨酰苯丙氨酸释放的甘氨酸部分被降解，部分被并入细菌细胞壁。这些二肽的行为与金黄色葡萄球菌悬液对杆菌溶素的灭活以及其C端氨基酸抗荚膜素在细胞外液中的出现情况相似。
