Methionine adenosyltransferase activity in erythrocytes and spinal cord of patients with sporadic amyotrophic lateral sclerosis.
The role of transmethylation mechanisms in the etiology of amyotrophic lateral sclerosis (ALS) is hitherto unexplored. The activity of L-methionine S-adenosyltransferase (MAT), a regulatory enzyme of S-adenosylmethionine biosynthesis, was investigated in erythrocytes of 21 patients with ALS, spinal cord specimens of 7 ALS patients, and matched controls. In ALS patients the activity of MAT in erythrocytes was sex-dependent. In comparison with controls, the male group presented a 33% higher V(max) (P < 0.05) and a 41% decrease in the affinity of MAT for methionine (K(m), P < 0.05). The type of ALS onset (limb or bulbar), age, or duration of the disease did not influence erythrocyte MAT activity. In the spinal cord, the activity of MAT was homogeneously distributed through dorsal horn, ventral horn, and white matter. Comparisons between data from controls and ALS patients and analysis of sex effect showed no significant differences. The kinetic difference of erythrocyte MAT in the male group of ALS patients might be interesting to explore since it is well known that there is a male predominance of 1.5 to 2. 5:1 in ALS.
Department of Neuroscience, Neurology, University Hospital, Uppsala, S-751 85, Sweden.
T
T
Ekegren
H
H
Askmark
S M
SM
Aquilonius
C
C
Gomes-Trolin
D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000097:blood / Q000201:enzymology* / Q000503:physiopathology; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008716:Methionine Adenosyltransferase / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D012016:Reference Values; D012737:Sex Factors; D013116:Spinal Cord / Q000201:enzymology*
D008716:Methionine Adenosyltransferase