PMID- 15037206
OWN - NLM
STAT- MEDLINE
DCOM- 20040405
LR  - 20151119
IS  - 0006-2952 (Print)
IS  - 0006-2952 (Linking)
VI  - 67
IP  - 3
DP  - 2004 Feb 1
TI  - Methioninase and selenomethionine but not Se-methylselenocysteine generate 
      methylselenol and superoxide in an in vitro chemiluminescent assay: implications 
      for the nutritional carcinostatic activity of selenoamino acids.
PG  - 547-54
AB  - Methylselenol from selenium metabolism is postulated to be and most experimental 
      evidence now indicates that it is the selenium metabolite responsible for the 
      dietary chemoprevention of cancers. Using the recombinant enzyme methioninase, 
      methylselenol-generating chemiluminesence by superoxide (O2*-) is shown to be 
      catalytically produced from L-selenomethionine and D,L-selenoethionine, but not 
      from methionine or L-Se-methylselenocysteine (SeMC). Methylselenol enzymaticaly 
      generated by methioninase activity from the substrate selenomethionine arises 
      from an initial putative selenium radical as measured by chemiluminesence in the 
      absence of glutathione (GSH). In the presence of GSH, superoxide was generated as 
      measured by chemiluminesence and superoxide dismutase inhibition of 
      chemiluminescence. Ascorbic acid also quenched the chemiluminesence from the 
      activity of methioninase with selenomethionine. Methylselenol and other redox 
      cycling selenium compounds are almost assuredly accountable for inducing 
      cell-cycle arrest and apoptosis in cancer cells in vitro and in vivo. 
      Methylselenol generated from selenomethionine by methioninase is catalytic alone 
      in oxidizing thiols, i.e. GSH, generating superoxide and inducing oxidative 
      stress in direct proportion to its concentration. Se-methylselenocysteine in vivo 
      is very likely carcinostatic in like manner to selenomethionine by generating 
      methylselenol from other enzymatic activity, i.e. beta-lyase or amino acid 
      oxidases.
FAU - Spallholz, Julian E
AU  - Spallholz JE
AD  - Food and Nutrition, College of Human Sciences, Texas Tech University, Lubbock, TX 
      79409, USA. julian.spallholz@ttu.edu
FAU - Palace, Vince P
AU  - Palace VP
FAU - Reid, Ted W
AU  - Reid TW
LA  - eng
PT  - Journal Article
PL  - England
TA  - Biochem Pharmacol
JT  - Biochemical pharmacology
JID - 0101032
RN  - 0 (Organoselenium Compounds)
RN  - 0 (Selenium Compounds)
RN  - 0CH9049VIS (Selenocysteine)
RN  - 11062-77-4 (Superoxides)
RN  - 964MRK2PEL (Selenomethionine)
RN  - EC 4.4.- (Carbon-Sulfur Lyases)
RN  - EC 4.4.1.11 (L-methionine gamma-lyase)
RN  - H6241UJ22B (Selenium)
RN  - K848JZ4886 (Cysteine)
RN  - TWK220499Z (selenomethylselenocysteine)
SB  - IM
MH  - Apoptosis
MH  - Carbon-Sulfur Lyases/*metabolism
MH  - Cells, Cultured
MH  - Cysteine/*analogs & derivatives/*metabolism
MH  - Humans
MH  - Luminescent Measurements
MH  - Organoselenium Compounds/*metabolism
MH  - Selenium/metabolism
MH  - Selenium Compounds/*metabolism
MH  - Selenocysteine/analogs & derivatives
MH  - Selenomethionine/*metabolism
MH  - Superoxides/*metabolism
EDAT- 2004/03/24 05:00
MHDA- 2004/04/06 05:00
CRDT- 2004/03/24 05:00
PHST- 2003/02/13 00:00 [received]
PHST- 2003/09/22 00:00 [accepted]
PHST- 2004/03/24 05:00 [pubmed]
PHST- 2004/04/06 05:00 [medline]
PHST- 2004/03/24 05:00 [entrez]
AID - S0006295203007330 [pii]
AID - 10.1016/j.bcp.2003.09.004 [doi]
PST - ppublish
SO  - Biochem Pharmacol. 2004 Feb 1;67(3):547-54. doi: 10.1016/j.bcp.2003.09.004.