Document Detail


Changes in the glucose-6-phosphatase complex in hepatomas.
MedLine Citation:
PMID:  8394504     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hepatomas tend to have a decreased glucose-6-phosphatase activity. We have observed phenotypic stability for this change in Morris hepatomas transplanted in rats. To determine if this decrease is selective for translocase functions or the hydrolase activity associated with glucose-6-phosphatase, we have compared activities in liver and hepatomas with glucose-6-phosphate or mannose-6-phosphate as substrates and with intact or histone-disrupted microsomes. In five out of seven subcutaneously transplanted rat hepatoma lines, the microsomal mannose-6-phosphatase activity was lower than in preparations from liver of normal or tumor-bearing rats. With liver microsomes and with most hepatoma microsomes, preincubation with calf thymus histones caused a greater increase in mannose-6-phosphatase than in glucose-6-phosphatase activity. In studies with liver and hepatoma microsomes there were similar increases in mannose-6-phosphatase activity with total calf thymus histones and arginine-rich histones. A smaller increase was seen with lysine-rich histones. The effect of polylysine was similar to the action of lysine-rich histones. There was only a small effect with protamine at the same concentration (1 mg/ml). Rat liver or hepatoma H1 histones gave only about half the activation seen with core nucleosomal histones. Our data suggested that microsomes of rat hepatomas tend to have decreased translocase and hydrolase functions of glucose-6-phosphatase relative to activities in untransformed liver.
Authors:
Q Xiao; I Jaspers; E Matthew; M A Lea
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Molecular and cellular biochemistry     Volume:  122     ISSN:  0300-8177     ISO Abbreviation:  Mol. Cell. Biochem.     Publication Date:  1993 May 
Date Detail:
Created Date:  1993-09-10     Completed Date:  1993-09-10     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0364456     Medline TA:  Mol Cell Biochem     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  17-24     Citation Subset:  IM    
Affiliation:
Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark 07103.
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MeSH Terms
Descriptor/Qualifier:
Animals
Enzyme Activation
Female
Glucose-6-Phosphatase / metabolism*
Histones / metabolism
Liver Neoplasms, Experimental / enzymology*
Male
Mannosephosphates / metabolism
Microsomes, Liver / metabolism
Neoplasm Transplantation
Rats
Chemical
Reg. No./Substance:
0/Histones; 0/Mannosephosphates; EC 3.1.3.9/Glucose-6-Phosphatase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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