Words similar to cephalosporins
Example sentences for: cephalosporins
How can you use “cephalosporins” in a sentence? Here are some example sentences to help you improve your vocabulary:
The F158A mutant exhibited higher K m values when using the cephalosporins as substrates, suggesting an interaction of the cephalosporins' substituents with the phenylalanine on the loop that extends over the active site.
On the other hand, the S224D mutant exhibited 3- to 50-fold higher K m values and 2- to 20-fold lower k cat values for the cephalosporins tested.
Wild-type L1 exhibited k cat values of 41 ± 1 s -1, 1.9 ± 0.1 s -1, 42 ± 1 s -1, and 82 ± 5 s -1for the cephalosporins, nitrocefin, cefoxitin, cefaclor, and cephalothin.
There are over 300 distinct β-lactamases known, and these enzymes have been grouped by a number of classification schemes [ 8 9 10 11 12 13 14 15 ] . For example, Bush has developed a scheme, based on the enzymes' molecular properties, that has four distinct β-lactamase groups [ 10 15 ] . One of the more alarming groups are the Bush group 3 enzymes, which are Zn(II) dependent enzymes that hydrolyze nearly all known β-lactam containing antibiotics and for which there are no or very few known clinical inhibitors [ 9 14 16 17 18 19 ] . The metallo-β-lactamases have been further divided by Bush into subgroups based on amino acid sequence identity: the Ba enzymes share a >23% sequence identity, require 2 Zn(II) ions for full activity, prefer penicillins and cephalosporins as substrates, and are represented by metallo-β-lactamase CcrA from Bacteroides fragilis, the Bb enzymes share a 11% sequence identity with the Ba enzymes, require only 1 Zn(II) ion for full activity, prefer carbapenems as substrates, and are represented by the metallo-β-lactamase imiS from Aeromonas sobria, and the Bc enzymes have only 9 conserved residues with the other metallo-β-lactamases, require 2 Zn(II) ions for activity, contain a different metal binding motif than the other metallo-β-lactamases, prefer penicillins as substrates, and are represented by the metallo-β-lactamase L1 from Stenotrophomonas maltophilia [ 9 ] . A similar grouping scheme (B1, B2, and B3) based on structural properties of the metallo-β-lactamases has recently been offered [ 41 ] . The diversity of the group 3 β-lactamases is best exemplified by the enzymes' vastly differing efficacies towards non-clinical inhibitors; these differences predict that one inhibitor may not inhibit all metallo-β-lactamases [ 18 20 21 22 23 24 25 26 27 28 29 ] . To combat this problem, we are characterizing a metallo-β-lactamase from each of the subgroups in an effort to identify a common structural or mechanistic aspect of the enzymes that can be targeted for the generation of an inhibitor.
As with the I164A mutant, the changes in K m and k cat for the penicillins and carbapenems were relatively small, as compared with the values obtained with the cephalosporins (Table 4).
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