Trypsin cleaves lysylproline in a hydroxyproline-rich glycoprotein from Zea mays.
Although trypsin is highly specific for lysyl and arginyl bonds, some peptide bonds, such as lysylproline, are generally trypsin-resistant, with rare exceptions as reported here. Trypsin cleaved a specific Lys-Pro bond in the chymotryptic peptide: Thr-Hyp-Ser-Hyp-Lys-Pro-Hyp-Thr-Pro-Lys-Pro-Thr-Hyp-Hyp-Thr-Tyr isolated from a Zea mays hydroxyproline-rich glycoprotein (HRGP). The daughter peptides, Thr-Hyp-Ser-Hyp-Lys-Pro-Hyp-Thr-Pro-Lys and Pro-Thr-Hyp-Hyp-Thr-Tyr, show cleavage of only one of the two Lys-Pro bonds in the parent peptide. From these and other data we suggest that there are two prerequisites for Lys-Pro cleavage: First, an extended helix characteristically present in proline or hydroxyproline-rich proteins; second, flexibility in two residues flanking the Lys-Pro bond.
Kieliszewski
M J
MJ
DOE Plant Research Laboratory, Michigan State University, East Lansing 48824.
Leykam
J F
JF
Lamport
D T
DT
D000595:Amino Acid Sequence; D002918:Chymotrypsin / Q000378:metabolism; D004151:Dipeptides; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006909:Hydroxyproline / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D013379:Substrate Specificity; D014357:Trypsin / Q000378:metabolism*; D003313:Zea mays
D004151:Dipeptides; D006023:Glycoproteins; D010446:Peptide Fragments; C039356:lysylproline; D002918:Chymotrypsin; D014357:Trypsin; D006909:Hydroxyproline