Characterization of the isoenzyme profile of beta-N-acetylhexosaminidase in the urine of newborns.
The urinary isoenzymes of beta-N-acetylhexosaminidase (Hex) in newborn infants were characterised by chromatography, electrophoresis, thermodynamic analysis and through substrate specificity. No qualitative difference was found for the major Hex A and Hex B isoenzymes between full-term or premature newborns and adults, although in the latter group the relative proportion of Hex B is much lower (18.5 +/- 2.7% vs. 36.3 +/- 1.0%). An additional minor enzyme form was found in some premature newborns, which eluted from the DEAE-cellulose column at a higher concentration of NaCl than Hex A and, like this isoenzyme, is able to hydrolyse 4-methylumbellipheryl-2-acetamido-2-deoxy-beta-D-glucopyranoside-6 -sulphate, which would suggest that it has alpha subunits in its molecule. These results do not confirm the hypothesis of other authors about the existence of a unique fetal Hex isoenzyme in neonatal urine which eluted before the application of the NaCl gradient, similarly to the Hex B.
Pérez
L F
LF
Laboratorio Central, Hospital General de Galicia-Clínico Universitario, Santiago de Compostela, Spain.
Martínez
M I
MI
Ribeiro
H M
HM
Pinto
R A
RA
Miranda
M C
MC
Tutor
J C
JC
D000328:Adult; D002848:Chromatography, DEAE-Cellulose; D004586:Electrophoresis; D005311:Fetal Hypoxia / Q000652:urine; D054818:Hexosaminidase A; D054819:Hexosaminidase B; D006801:Humans; D007231:Infant, Newborn / Q000652:urine*; D007234:Infant, Premature / Q000652:urine; D007527:Isoenzymes / Q000652:urine; D001619:beta-N-Acetylhexosaminidases / Q000652:urine*
D007527:Isoenzymes; D054818:Hexosaminidase A; D054819:Hexosaminidase B; D001619:beta-N-Acetylhexosaminidases