Figure 1.
Interconversion of thiamine derivatives in a model human cell.
1, cytosolic thiamine diphosphokinase (TPK); 2, cytosolic thiamine diphosphatase (also hydrolyzes nucleoside diphosphates); 3, thiamine monophosphatase (hypothetical); 4, mitochondrial membrane-associated ThTP synthase; 5, cytosolic adenylate kinase; 6, cytosolic 25-kDa ThTPase; 7, cytosolic ThDP adenylyl transferase; 8, AThTP hydrolase (hypothetical). The mechanisms of AThDP synthesis and degradation are unknown. Δp, transmembrane H+ gradient. Updated from [21].
Table 1.
Distribution of thiamine derivatives in human whole blood, plasma and CSF.
Table 2.
Distribution of thiamine derivatives in human biopsies.
Table 3.
Distribution of thiamine derivatives in normal and ischemic human liver.
Table 4.
Distribution of thiamine derivatives in human embryonic tissues and adult gynecological specimen.
Table 5.
Soluble 25-kDa ThTPase activities in human tissues.
Table 6.
Thiamine compounds in human semen.
Table 7.
Thiamine derivatives in brain samples.
Table 8.
ThTP and AThTP in cultured cell lines.
Figure 2.
25-kDa ThTPase activities in the brain and cultured cell lines from humans and mice.
(A) ThTPase specific activities measured at pH 8.5, at 37°C and at a Mg2+ concentration of 10 mM (means ± SD, n = 3) in mouse and human brain and cell lines. (B) pH profile of ThTPase activity from various sources (means ± SD, n = 2). The buffers (50 mM final concentration) used were: Pipes (pH 6.5), Mops (pH 7.1), Hepes (pH 7.5), Taps (pH 8.0), Bis-Tris-Propane (pH 8.5) and Ches (pH 9.1 and 9.5).
Figure 3.
Amplification of 25-kDa ThTPase mRNA in different cell lines by RT-PCR.
(SL, standard ladder; S, SN-K-BE; C, C2C12; L, LN-18).
Figure 4.
Western blots of human tissues and cultured cell lines using a commercial mouse polyclonal antibody.
The antibody was raised against human recombinant 25-kDa hThTPase. The samples were homogenized and centrifuged (20 000× g, 30 min). In the case of the biological samples, 40 µg of cytosolic protein were loaded on the gel; for hThTPase, the amount was 0.5 µg. The arrow indicates the location of 25-kDa hThTPase. (Ex, ectocervix; En, endometrium; hT, human recombinant ThTPase; L, human LN-18 glioblastoma cells; S, human SK-N-BE neuroblastoma cells; U, uterus; Tr, trophoblast).