The localization of fructose 1,6-bisphosphatase (D-Fru-1,6-P-2-1-phosp
hohydrolase, EC 3.1.3.11) in rat kidney and liver was determined immun
ohistochemically using a polyclonal antibody raised against the enzyme
purified from pig kidney. The immunohistochemical analysis revealed t
hat the bisphosphatase was preferentially localized in hepatocytes of
the periportal region of the liver and was absent from the perivenous
region. Fructose-1,6-bisphosphatase was also preferentially localized
in the cortex of the kidney proximal tubules and was absent in the glo
meruli, loops of Henle, collecting and distal tubules, and in the rena
l medulta. As indicated by immunocytochemistry using light microscopy
and confirmed with the use of reflection confocal microscopy, the enzy
me was preferentially localized in a perinuclear position in the liver
and the renal cells. Subcellular fractionation studies followed by en
zyme activity assays revealed that a majority of the cellular fructose
-1,6-bisphosphatase activity was associated to subcellular particulate
structures. Overall, the data support the concept of metabolic zonati
on in liver as well as in kidney, and establish the concept that the F
ructose-1,6-bisphosphatase is a particulate enzyme that cannot be cons
idered a soluble enzyme in the classical sense. (C) 1996 Wiley-Liss, I
nc.