PMID- 18675352
OWN - NLM
STAT- MEDLINE
DCOM- 20090219
LR  - 20131121
IS  - 0953-7562 (Print)
IS  - 0953-7562 (Linking)
VI  - 112
IP  - Pt 12
DP  - 2008 Dec
TI  - Identification of nitrogen mineralization enzymes, L-amino acid oxidases, from 
      the ectomycorrhizal fungi Hebeloma spp. and Laccaria bicolor.
PG  - 1453-64
LID - 10.1016/j.mycres.2008.06.023 [doi]
AB  - Amino acids are major nitrogen sources in soils and they harbour a central 
      position in the nitrogen metabolism of cells. We determined whether Hebeloma spp. 
      and Laccaria bicolor expressed the enzyme L-amino acid oxidase (LAO), which 
      catalyses the oxidative deamination of the alpha-amino group of L-amino acids. We 
      measured LAO activities from the mycelial extracts of seven laboratory-grown 
      fungal strains with three methods, and we measured how LAO activities were 
      expressed in one Hebeloma sp. strain grown on four nitrogen sources. Hebeloma 
      spp. and L. bicolor converted L-phenylalanine, but not D-phenylalanine, to 
      hydrogen peroxide, 2-oxoacid, and ammonia, suggesting that they expressed LAO 
      enzymes. The enzymes utilized five out of seven tested L-amino acids as 
      substrates. LAO activities were maximal at pH 8, where Michaelis constant (Km) 
      values were 2-5mm. The LAO of Hebeloma sp. was expressed on every nitrogen source 
      analysed, and the activities were the highest in mycelia grown in nitrogen-rich 
      conditions. We suggest that LAO is a mechanism for cellular amino acid catabolism 
      in Hebeloma spp. and L. bicolor. Many soil bacteria and fungi also express LAO 
      enzymes that have broad substrate specificities. Therefore, LAO is a potential 
      candidate for a mechanism that catalyses nitrogen mineralization from amino acids 
      at the ecosystem level.
FAU - Nuutinen, Jaro T
AU  - Nuutinen JT
AD  - University of Helsinki, Department of Applied Biology, P.O. Box 27, FI-00014 
      University of Helsinki, Finland. jaro.nuutinen@iki.fi
FAU - Timonen, Sari
AU  - Timonen S
LA  - eng
SI  - GENBANK/EF564167
SI  - GENBANK/EF564168
SI  - GENBANK/EF564169
SI  - GENBANK/EF564170
SI  - GENBANK/EF564171
SI  - GENBANK/EF564172
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080715
PL  - England
TA  - Mycol Res
JT  - Mycological research
JID - 8913481
RN  - 0 (DNA, Fungal)
RN  - 0 (DNA, Intergenic)
RN  - 0 (Keto Acids)
RN  - 0 (Quaternary Ammonium Compounds)
RN  - BBX060AN9V (Hydrogen Peroxide)
RN  - EC 1.4.3.2 (L-Amino Acid Oxidase)
SB  - IM
MH  - Base Sequence
MH  - DNA, Fungal/chemistry/genetics
MH  - DNA, Intergenic/chemistry/genetics
MH  - Hebeloma/*enzymology/genetics
MH  - Hydrogen Peroxide/metabolism
MH  - Keto Acids/metabolism
MH  - L-Amino Acid Oxidase/genetics/*isolation & purification/metabolism
MH  - Laccaria/*enzymology/genetics
MH  - Molecular Sequence Data
MH  - Mycelium/enzymology/genetics
MH  - Mycorrhizae/*enzymology/genetics
MH  - Phylogeny
MH  - Quaternary Ammonium Compounds/metabolism
EDAT- 2008/08/05 09:00
MHDA- 2009/02/20 09:00
CRDT- 2008/08/05 09:00
PHST- 2007/06/06 00:00 [received]
PHST- 2008/01/28 00:00 [revised]
PHST- 2008/06/16 00:00 [accepted]
PHST- 2008/08/05 09:00 [pubmed]
PHST- 2009/02/20 09:00 [medline]
PHST- 2008/08/05 09:00 [entrez]
AID - S0953-7562(08)00181-0 [pii]
AID - 10.1016/j.mycres.2008.06.023 [doi]
PST - ppublish
SO  - Mycol Res. 2008 Dec;112(Pt 12):1453-64. doi: 10.1016/j.mycres.2008.06.023. Epub 
      2008 Jul 15.