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Diss Factsheets

Administrative data

additional toxicological information
Type of information:
experimental study
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Referenceopen allclose all

Reference Type:
Vicinal Diamines as Pyrroloquinoline Quinone-directed Irreversible Inhibitors of Lysyl Oxidase
Stephen N. Gacheru, Philip C. Trackman, Susan D. Calaman, Frederick T. Greenaway, and
Herbert M. Kagan
Bibliographic source:
Vol. 264, No. 22, Issue of August 5, pp. 12963-12969,1989
Reference Type:
review article or handbook
Enzymology of Lysyl Oxidase
Herbert M. Kagan, Stephen N. Gacheru, Philip C. Trackman, Susan D. Calaman
and Frederick T. Greenaway
Bibliographic source:
J. A. Jongejan and 1. A. Duine (eds.), PQQ and Quinoproteins, 317-326.
© 1989 by Kluwer Academic Publishers.

Materials and methods

Principles of method if other than guideline:
The authors purified lysyl oxidase (LOX) from bovine aorta, defined one enzyme unit and quantified functional active site content. Afterwards, the enzyme was assayed against DCH by a peroxidase-coupled fluorescence method in a defined reaction mixture. Due to beginning enzyme inhibition at concentrations starting from 0.8 µM, steady-state kinetic analyses were restricted to concentrations not greater than 1.2 µM cis-1,2-diaminocyclohexane (0.2, 0.5, 0.8, 1.2 µM). The assays assessing inhibition of LOX activity against cis- and trans- isomers of 1,2-diaminocyclohexane contained enzyme active site concentrations of 0.02 µM and n-hexylamine as productive substrate. Initial rates of substrate oxidation were assessed from the slopes of fluorescence tracings versus time after addition of the enzyme (20 s to 3 min). Steady-state kinetic constants were calculated according to Michaelis-Menten equation using the Fortram program of Cleland (Cleland, W. W. (1979) Methods Enzymol. 63, 103-138) applying a least squares fitting procedure to the Michaelis-Menten equation. Additionally, enzyme inhibition in the absence of a productive substrate was assessed by incubation of 50 mM cis-DCH with LOX for 15 min at 37°C in the reaction mixture. Time dependence for the expression of irreversible inhibition was assessed in a further experiment as well.
GLP compliance:
not specified

Test material

Test material form:
not specified
Details on test material:
Please refer to entry 'Specific details on test material used for the study'
Specific details on test material used for the study:
cis-1,2-diaminocyclohexane (CAS no.: 1436-59-5)

trans-1,2-diaminocyclohexane (CAS no.: 1121-22-8)

both substances obtained from Alfa products (Thermo Fisher Scientific, Waltham, MA, USA)

Results and discussion

Any other information on results incl. tables

Cis-1,2-diaminocyclohexane was shown to be a more potent inhibitor of elastin oxidation by LOX ( IC50 = 1.5 µM) than trans-1,2-diaminocyclohexane (IC50 > 10 mM, extrapolated). A Lineweaver-Burke plot showed that the inhibition is competitve with a KI of 3.8 x10-7M measured under the initial rate conditions (20s-3min) and at the low concentrations (0.2, 0.5, 0.8, 1.2 µM) used. After 15 min incubation of LOX with 50 mM cis-DCH in the absence of a productive substrate, LOX was completely and irreversibly inhibited. Time dependence assays showed that the rates of enzyme activity loss increased with increasing cis-DCH concentrations, following first order kintetics with kinact = 18 min-1.

Applicant's summary and conclusion

Cis-1,2-diaminocyclohexane but not trans-1,2-diaminocyclohexane is a potent lysyl oxidase inhibitor.