An Aneurinibacillus sp. strain AM-1 produces a proline-specific aminopeptidase useful for collagen degradation.
OBJECTIVE
We have been for a species of thermophilic bacteria that can effectively decompose collagen and collagen peptides that tend to be hard-to-degrade proteins because of their high content of proline residues. This study focused upon the enzymatic degradation of prolyl peptides by thermophilic bacteria.


RESULTS
A strain, AM-1, producing a proline-specific aminopeptidase was isolated using a medium containing gelatin that was taken from soil samples collected at Arima Hot Spring located near Kobe, Japan. The strain showed the strongest level of hydrolysing activity toward prolyl-p-nitroanilide, and the activity proved to be thermostable. Phylogenetic analysis based on 16S rDNA sequences revealed that the isolated strain AM-1 was closest to Aneurinibacillus thermoaerophilus DSM10154T in its characteristics. Analysis of the purified proline-specific aminopeptidase suggested that the enzyme is an aminopeptidase containing metal that includes important disulphide bond(s). The strain AM-1 aminopeptidase has more similarities with leucyl aminopeptidases, but its activity level differs greatly with prolyl peptides.


CONCLUSIONS
The proline-specific aminopeptidase from strain AM-1 is the first from the genus Aneurinibacillus and may be a new type of aminopeptidase for hydrolysing prolyl peptide. This enzyme also contributed to the degradation of collagen when used in combination with another collagenolytic protease.


CONCLUSIONS
The proline-specific aminopeptidase obtained from strain AM-1 may be used in the treatment of wastewater containing collagen that is encountered in the meat industries, and for decreasing bitter peptides in milk products.
Murai
A
A
Department of Applied Biochemistry, Kyoto Prefectural University, Shimogamo, Sakyo, Kyoto, Japan.
Tsujimoto
Y
Y
Matsui
H
H
Watanabe
K
K
D000626:Aminopeptidases / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D001406:Bacillaceae / Q000378:metabolism*; D015153:Blotting, Western / Q000379:methods; D003094:Collagen / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D020539:Sequence Analysis, Protein; D018508:Water Purification
D003094:Collagen; D011392:Proline; D000626:Aminopeptidases