Esterification of D-mannoheptulose confers to the heptose inhibitory action on D-glucose metabolism in parotid cells.
D-mannoheptulose, but not its hexaacetate ester, inhibits, in a competitive manner, D-glucose phosphorylation by either purified beef heart hexokinase or crude parotid gland homogenates. Yet, D-mannoheptulose hexaacetate, but neither the unesterified heptose nor acetate or its methyl ester, inhibits D-[5-3H]glucose utilization and D-[U-14C]glucose conversion to 14CO2 and 14C-labelled acidic metabolites and amino acids in intact isolated parotid cells. It is proposed, therefore, that D-mannoheptulose hexaacetate crosses efficiently the plasma membrane of parotid cells and, after intracellular hydrolysis, allows inhibition of D-glucose phosphorylation by the unesterified heptose. The ester of D-mannoheptulose could thus represent a useful tool to inhibit hexose phosphorylation and interfere with cell growth in cells otherwise resistant to the heptose.
Malaisse
W J
WJ
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Kadiata
M M
MM
Scruel
O
O
Sener
A
A
D000085:Acetates / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D004952:Esters / Q000494:pharmacology; D005260:Female; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D006593:Hexokinase / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism; D008356:Mannoheptulose / Q000737:chemistry* / Q000494:pharmacology*; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D000085:Acetates; D004952:Esters; D006601:Hexoses; D008356:Mannoheptulose; D006593:Hexokinase; D005947:Glucose