Elsevier

Analytical Biochemistry

Volume 99, Issue 1, 15 October 1979, Pages 53-64
Analytical Biochemistry

Sensitive substrates for human leukocyte and porcine pancreatic elastase: A study of the merits of various chromophoric and fluorogenic leaving groups in assays for serine proteases

https://doi.org/10.1016/0003-2697(79)90043-5Get rights and content

Abstract

Five sensitive substrates of human leukocyte and porcine pancreatic elastase having the sequence MeO-Suc-Ala-Ala-Pro-Val-X where -X is -NA (4-nitroanilide), -SBzl (thiobenzyl ester), -OEt, -AMC (4-methyl-7-coumarylamide), or -NNapOMe (1-methoxy-3-naphthylamide), were synthesized. The kinetic constants for the enzymatic hydrolysis as well as the sensitivity of each substrate are reported. Hydrolysis of the peptide -AMC and -NNapOMe derivatives were followed by monitoring spectrofluorometrically the release of H-AMC and H-NNapOMe, respectively. Cleavage of the thiobenzyl ester yields benzyl mercaptan as the hydrolysis product. Its release was monitored at 412 nm by reaction with Ellman's reagent [5,5′-dithiobis(2-nitrobenzoic acid)] in the assay mixture to produce the 3-carboxy-4-nitrothiophenoxide anion or at 324 nm by reaction with 4,4′-dithiodipyridine to produce 4-thiopyridone. Hydrolysis of the ethyl ester was measured using a coupled assay with NAD+ and liver alcohol dehydrogenase. The NADH+ formed upon oxidation of the ethanol released from cleavage of the ester was followed at 340 nm. MeO-Suc-Ala-Ala-Pro-Val-SBzl, the best substrate of the series, was capable of detecting as little as 2.4 pm (0.072 ng/ml) of active-site titrated human leukocyte elastase and 5.8 pm (0.15 ng/ml) of active-site titrated porcine pancreatic elastase using 4,4′-dithiodipyridine. The corresponding values with Ellman's reagent were 5.0 pm (0.15 ng/ml) and 7.4 pm (0.19 ng/ml), respectively. Advantages of this substrate are its high kcatKm values and ease of synthesis. One disadvantage is the interference of high concentration of thiols with the assay. The peptidyl-AMC is almost as sensitive as the thiobenzyl ester and can detect 11 pm of HL elastase and 18 pm of PP elastase. An advantage of this substrate is the fact that cleavage involves a peptide bond. Disadvantages are relatively low kcatKm values and greater difficulty in synthesis. The peptidyl-NNapOMe has possible utility in histochemical studies due to the low intrinsic fluorescence of the substrate relative to the peptidyl-AMC. For a rate assay it has a lower sensitivity than either the thiobenzyl ester or peptidyl-AMC. The coupled liver alcohol dehydrogenase-ethyl ester assay offers no advantages except in cases where the ester substrate is commercially available. The 4-nitroanilide assay enjoys moderate sensitivity and is extremely convenient for routine use. Except for the peptidyl ethyl ester assay, all of the human leukocyte elastase assays reported in this paper are vastly more sensitive than any other existing assay for this protease.

References (37)

  • P.M. Tuhy et al.

    FEBS Lett

    (1975)
  • J.C. Powers et al.

    Biochim. Biophys. Acta

    (1977)
  • K. Nakajima et al.

    J. Biol. Chem

    (1979)
  • M. Zimmerman et al.

    Anal. Biochem

    (1976)
  • M. Zimmerman et al.

    Anal. Biochem

    (1977)
  • T. Kato et al.

    Biochem. Med

    (1978)
  • S.A. Clavin et al.

    Anal. Biochem

    (1977)
  • R.M. Huseby et al.

    Thromb. Res

    (1977)
  • J. Bieth et al.

    Biochem. Biophys. Res. Commun

    (1973)
  • G. Feinstein et al.

    Biochem. Biophys. Res. Commun

    (1973)
  • J. Bieth et al.

    Biochem. Med

    (1974)
  • D.Y. Twumasi et al.

    J. Biol. Chem

    (1977)
  • M. Zimmerman et al.

    Biochim. Biophys. Acta

    (1977)
  • D.A. Farmer et al.

    J. Biol. Chem

    (1975)
  • J.C. Powers et al.
  • B.F. Erlanger et al.

    Arch. Biochem. Biophys

    (1961)
  • D.R. Grassetti et al.

    Arch. Biochem. Biophys

    (1967)
  • G.L. Ellman

    Arch. Biochem. Biophys

    (1959)
  • Cited by (218)

    • Kinetic and structural analysis of fluorescent peptides on cotton cellulose nanocrystals as elastase sensors

      2015, Carbohydrate Polymers
      Citation Excerpt :

      However, the benefit of the greater surface area of nanocrystalline cellulose has been well documented (Eyley & Thielemans, 2011; Habibi, Chanzy, & Vignon, 2006; Siqueira, Bras, & Dufresne, 2009), and the benefit of surface exposed peptides in this study is proven by the good results in kinetic profile as discussed below. DS determinations have previously been made for the determination of surface area of nanocrystalline cellulose using a variety of methods (Castillo, Nakajima, Zimmerman, & Powers, 1979; Eyley & Thielemans, 2011; Siqueira et al., 2009). For example DS levels of surface hydroxymethyl groups (a DS of 0.09) are considered stoichiometric for TEMPO oxidized nanocellulose (Castillo et al., 1979).

    View all citing articles on Scopus
    View full text