Positional effects in the neprilysin (neutral endopeptidase) reaction.
Neprilysin is a peptidase which has a specificity directed toward cleavage on the amino side of hydrophobic residues. In addition an active site arginine on the enzyme can interact with the C-terminal carboxylate of a substrate. The importance of the position of the hydrophobic residue relative to the C-terminus of the substrate has been investigated using a series of peptides containing one or two cleavage sites. With a hexapeptide series succ-(GLy)x-Phe-(Gly)y-OH, where x = 1 to 5 and y = 5 to 1 respectively, a approximately 25-fold increase in the specificity constant kcat/Km was observed when Phe was adjacent to the C-terminal Gly residue. With peptide-free acids containing two cleavable bonds (X and Y) of the type succ-Gly-X-Gly-Y-Gly-OH, cleavage was observed at the Y residue. However, when the two cleavable bonds were adjacent, succ-Gly-Gly-X-Y-Gly-OH, cleavage of a tripeptide was observed even when the residue in position X was one cleaved poorly when presented as the sole cleavage site. These results demonstrate a preference by the enzyme for the placement of a hydrophobic residue in the P'2 position.
Quay
T
T
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.
Slaughter
C
C
Davis
T P
TP
Merrill
B J
BJ
Hersh
L B
LB
D000595:Amino Acid Sequence; D000818:Animals; D001839:Bombesin / Q000737:chemistry / Q000378:metabolism; D005998:Glycine; D007668:Kidney / Q000201:enzymology; D008969:Molecular Sequence Data; D015260:Neprilysin / Q000302:isolation & purification / Q000378:metabolism*; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism*; D010649:Phenylalanine; D051381:Rats; D013050:Spectrometry, Fluorescence; D013379:Substrate Specificity
D009842:Oligopeptides; D010649:Phenylalanine; D015260:Neprilysin; D001839:Bombesin; D005998:Glycine