ISSN:
0006-3592
Keywords:
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A sensitive cup plate assay method for lysine on large plates using S. faecalis ATCC 6057 as the test organism is described in detail. Well-defined zones of dense growth were obtained in a rectilinear dose - response range from 5 to 3000 μg. of L-lysine/ml. Comparative assays on twelve different samples were carried out using the turbidimetric tube assay method with Leuc. mesenteroides ATCC 8042 and the cup plate method with S. faecalis ATCC 6057. Good agreement between the two assay methods was obtained for five samples. For the remaining seven samples the tube assay values were appreciably higher than those obtained by the plate method. This discrepancy is discussed. Pure lysine added to various sample extracts could be quantitatively recovered. The specificity of the lysine requirement of S. faecalis ATCC 6057 in the plate assay was also investigated. Under certain experimental conditions, a weak and variable response was obtained with D-lysine and the polyamines cadaverine, spermine, and spermidine. There was generally no difficulty in distinguishing the D-lysine and polyamine growth zones from the L-lysine growth zones. This growth effect of D-lysine and polyamines could be diminished and even completely abolished by increasing the DL-hydroxylysine hydrochloride level in the plate medium. The lysine peptides glycyl-L-lysine and L-lysylglycine gave excellent growth zones of the same appearance as those produced by L-lysine. The activity of these two peptides in cup tests were on a molar basis about 70% of that of L-lysine.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260050209
