Sensitive substrates for neprilysin (neutral endopeptidase) and thermolysin that are highly resistant to serine proteases.
Tripeptide derivatives like 3-carboxypropanoylalanyl-alanyl-leucine 4-nitroanilide or 3-carboxypropanoyl-alanyl-alanyl-phenylalanine 4-nitroanilide are very sensitive substrates for neprilysin (k cat > 10(2)s(-1); k cat/Km > or = 10(6) s(-1) x M(-1)) and are widely employed in investigations of the enzyme. However, these compounds are also good substrates for the serine proteases chymotrypsin and subtilisin (k cat approximately 1s(-1)-34s(-1)). By substituting the N-terminal alanine of the substrates with proline, the catalytic efficiency of the enzymic reaction, by the serine proteases, is diminished by 2-3 orders of magnitude, whereas that by neprilysin and theromlysin decreases only slightly. These effects demonstrate that structural alterations in peptide substrates that impair secondary sub-site interactions with one class of peptidases may enhance the selectivity of the substrates towards another class of peptidases.
Spungin-Bialik
A
A
Sackler Institute of Molecular Medicine, Sackler Faculty of Medicine, Tel Aviv University, Israel.
Ben-Meir
D
D
Fudim
E
E
Carmeli
S
S
Blumberg
S
S
D000595:Amino Acid Sequence; D000814:Aniline Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D002918:Chymotrypsin / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D015260:Neprilysin / Q000378:metabolism*; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D013381:Subtilisins / Q000378:metabolism*; D013820:Thermolysin / Q000378:metabolism*
D000814:Aniline Compounds; D009842:Oligopeptides; D013381:Subtilisins; D002918:Chymotrypsin; D015260:Neprilysin; D013820:Thermolysin