{Reference Type}: Journal Article
{Title}: O2 Carrier Myoglobin Also Exhibits β-Lactamase Activity That Is Regulated by the Heme Coordination State.
{Author}: Tang S;Pan AQ;Wang XJ;Gao SQ;Tan XS;Lin YW;
{Journal}: Molecules
{Volume}: 27
{Issue}: 23
{Year}: Dec 2022 2
{Factor}: 4.927
{DOI}: 10.3390/molecules27238478
{Abstract}: Heme proteins perform a variety of biological functions and also play significant roles in the field of bio-catalysis. The β-lactamase activity of heme proteins has rarely been reported. Herein, we found, for the first time, that myoglobin (Mb), an O2 carrier, also exhibits novel β-lactamase activity by catalyzing the hydrolysis of ampicillin. The catalytic proficiency ((kcat/KM)/kuncat) was determined to be 6.25 × 1010, which is much higher than the proficiency reported for designed metalloenzymes, although it is lower than that of natural β-lactamases. Moreover, we found that this activity could be regulated by an engineered disulfide bond, such as Cys46-Cys61 in F46C/L61C Mb or by the addition of imidazole to directly coordinate to the heme center. These results indicate that the heme active site is responsible for the β-lactamase activity of Mb. Therefore, the study suggests the potential of heme proteins acting as β-lactamases, which broadens the diversity of their catalytic functions.