Search International and National Patent Collections
Some content of this application is unavailable at the moment.
If this situation persists, please contact us atFeedback&Contact
1. (US5334703) Chromogenic substrate
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters
I claim:
1. Peptide derivatives having the general formula:
R 1 -A 1 -A 2 -A 3 -A 4 -R 2 or its salt
wherein
R 1 =H or a protective group
A 1 =H, Ile, Leu or Val
A 2 =Glu, Asp, Ser, or Thr
A 3 =Gly or Glyc
A 4 =Arg or Lys
R 2 =is a group that upon enzymatic hydrolysis gives para-nitroaniline (pNA),
with the proviso that A 3 is Gly when A 4 is Lys and Glyc when A 4 is Arg.
2. Peptide derivatives according to claim 1 wherein A 1 =Ile.
3. Peptide derivatives according to claim 1 having the formula selected from the group consisting of:
α-Ac-Ile-Glu-Gly-Lys-pNA,
α-Ac-Ile-Ser-Gly-Lys-pNA,
α-Ac-Ile-Thr-Gly-Lys-pNA, and
α-Ac-Ile-Glu-Glyc-Arg-pNA.
4. A method for quantitatively determining bacterial endotoxins in a sample which comprises incubating the sample with a Limulus clotting enzyme and a substrate for said enzyme, wherein said substrate is a peptide derivative having the following formula:
R 1 -A 1 -A 2 -A 3 -A 4 -R 2 or its salt
where
R 1 =H or a protective group
R 1 =H, Ile, Leu or Val
A 2 =Glu, Asp, Ser, or Thr
A 3 =Gly or Glyc
A 4 =Arg or Lys
R 2 =an aromatic or heterocyclic group which by enzymatic hydrolysis gives a compound R 2 -NH 2 which can be determined quantitatively,
with the proviso that A 3 is Gly when A 4 is Lys and Glyc when A 4 is Arg.
5. The method of claim 4 when A is Ile.
6. The method of claim 5 wherein said peptide derivative is selected from the group consisting of:
α-Ac-Ile-Glu-Gly-Lys-pNA,
α-Ac-Ile-Ser-Gly-Lys-pNA,
α-Ac-Ile-Thr-Gly-Lys-pNA, and
α-Ac-Ile-Glu-Glyc-Arg-pNA.
7. The method of claim 4 wherein said clotting enzyme is Limulus Amebocyte Lysate.
8. The method of claim 4 wherein R 2 -NH 2 is para-nitroaniline.