Bactident Aminopeptidase

Bactident^® Aminopeptidase

EMD Cat. No. 1.13301.0001

50 test strips

Test strip with a reactive zone for detecting L-alanine aminopeptidase in microorganisms.

L-alanine aminopeptidase is an enzyme localized in the bacterial cell wall which cleaves the amino acid L-alanine from various peptides. Significant activity is found almost only in Gram-negative microorganisms, all Gram-positive or Gram-variable microorganisms so far studied display no or very weak activity (CERNY 1978, OTTE and TOLLE 1980, CARLONE et al. 1982). The aminopeptidase test thus provides a reliable method for determining the Gram behaviour of microorganisms. It does not replace the Gram-staining, as it cannot show morphology!

Typical Composition (g/liter)	Note
Literature	Picture/Image

Mode of Action
In the test strips the substrate L-alanine-4-nitroanilide is split by L-alanine aminopeptidase into L-alanine and 4-nitroaniline. The latter compound causes the bacterial suspension to turn yellow, this is regarded as evidence for the presence of L-alanine aminopeptidase (CERNY 1976, COSTIN et al. 1983).

Experimental Procedure and Evaluation
Remove a single, isolated, well-developed colony from the culture medium and suspend it in a test tube containing 0.2 ml distilled water to give a clearly opalescent suspension. Place a test strip in the tube and incubate for 10 to a maximum of 30 °C. Note the color of the suspension and compare it with the scale on the package.

Yellow coloration:
Aminopeptidase-positive Gram-negative.
Exceptions:
Bacteroides vulgatus, Bacteroides fragilis, Campylobacter sp., Veillonella parvula.
No yellow coloration:
Aminopeptidase-negative Gram-positive.

Composition
L-Alanine-4-nitroanilide hydrochloride; buffering agents.

Note
The culture media on which the colonies growth, should not contain any indicators or dyes. It is not advised to perform the tests with strongly pigmented colonies.

Literature

CARLONE, G.M., VALDEZ, M.J., a. PICKET, M.J.: Methods for Distinguishing Gram-Positive Bacteria. - J. Clin. Microbiol., 16; 1157-1159 (1982).
CERNY, G.: Method for Distinction of the Gram-Negative from Gram-Positive Bacteria. - Eur. J. App. Microbiol., 3; 223-225 (1976).
CERNY, G.: Studies on the Aminopeptidase-Test for the Distinction of Gram-Negative from Gram-Positive Bacteria. - Eur. J. Appl. Microbiol. Biotechnol., 5; 113-122 (1978).
COSTIN, J.D., KAPPNER, M., u. SCHMIDT, W.: Differenzierung von Gram-positiven und Gram-negativen Bakterien mit dem L-Alanin-Aminopeptidase-Test. - Forum Mikrobiol., 351-353 (1983).
OTTE, I., u. TOLLE, A.: Zur Aminopeptidase- und Gram-Reaktion von Bakterien. - Milchwiss., 35; 215-217 (1980).

Bactident Aminopeptidase