History of penicillin History of penicillin The history of penicillin follows a number of observations and discoveries of apparent evidence of antibiotic activity in molds before the modern isolation of the chemical penicillin in 1928. There are anecdotes about ancient societies using molds to treat infections, and in the following centuries many people observed the inhibition of bacterial growth by various molds. However, it is unknown if the species involved were "Penicillium" species or if the antimicrobial substances produced were penicillin. The Scottish physician Alexander Fleming was the first to suggest that a "Penicillium" mold must secrete an antibacterial substance, and the first
Penicillin binding proteins Penicillin binding proteins Penicillin-binding proteins (PBPs) are a group of proteins that are characterized by their affinity for and binding of penicillin. They are a normal constituent of many bacteria; the name just reflects the way by which the protein was discovered. All β-lactam antibiotics (except for tabtoxinine-β-lactam, which inhibits glutamine synthetase) bind to PBPs, which are essential for bacterial cell wall synthesis. PBPs are members of a subgroup of enzymes called transpeptidases. Specifically, PBPs are DD-transpeptidases. There are a large number of PBPs, usually several in each organism, and they are found as both membrane-bound and cytoplasmic proteins. For