Human microsomal glucose-6-phosphatase system.

R C Nordlie; K A Sukalski; W T Johnson

doi:10.1007/bf02072079

Home/Archive/PubMed

PubMed · 8391443

Human microsomal glucose-6-phosphatase system.

R C Nordlie·K A Sukalski·W T Johnson

View original source ↗Export metadata ↓

Abstract

The discovery of glucose-6-phosphatase (EC 3.1.3.9) and of its physiological function in releasing glucose from the liver are discussed briefly. The identification by the Coris of glucose-6-phosphatase deficiency as the underlying defect in certain cases of glycogenosis (type I glycogenosis; von Gierke disease) is described. Characteristics of the catalyst, with a focus on its multiplicity of functions and multicomponent character, are considered with an emphasis on the human liver enzyme. Pioneering studies from the author's laboratory leading to the characterization of two variants of type I glycogenosis, types Ib and Ic, are described.

Explore related subjects

Glucose-6-Phosphatase Glycogen Storage Disease Type I Humans Microsomes, Liver Journal Article Research Support, U.S. Gov't, P.H.S.Review

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

R C Nordlie, K A Sukalski, W T Johnson. 1993. Human microsomal glucose-6-phosphatase system.. https://doi.org/10.1007/bf02072079

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1999

Identification of three novel mutations (Q54P, W70X and T108I) in the glucose-6-phosphatase gene of patients with glycogen storage disease type Ia. Mutation in brief no. 256. Online.

Three novel mutations, Q54P, W70X and T1081, were identified in the gene encoding glucose-6-phosphatase in three patients with glycogen storage disease type Ia. Two sibs of Portuguese origin were homozygous for the Q54P mutation whereas the third patient, originating from both France and Lebanon, was a compound heterozygote for the W70X and T108I mutations. Glycogen storage disease type Ia is a heterogeneous autosomal recessive condition.

Glucose-6-Phosphatase↗

PubMed1995

The glucose-6-phosphatase system in human development.

The classical role of glucose-6-phosphatase in liver and kidney is the production of glucose for release into blood. In liver, glucose-6-phosphatase catalyses the terminal step of glycogenolysis and gluconeogenesis. Abnormally low hepatic glucose-6-phosphatase activity is found in human genetic deficiencies i.e. glycogen storage disease type I and in cases of developmental delay, found predominantly in preterm infants. In contrast, abnormally high liver glucose-6-phosphatase occurs in poorly controlled or untreated diabetes mellitus. Hepatic glucose-6-phosphatase is an integral endoplasmic reticulum (and nuclear membrane) protein and it is part of a multicomponent system. Its active site is situated inside the lumen of the endoplasmic reticulum and transport proteins are needed to allow its substrates glucose-6-phosphate (and pyrophosphate) and its products phosphate and glucose to cross the endoplasmic reticulum membrane. In addition, a calcium binding protein is also associated with the glucose-6-phosphatase enzyme. Immunohistochemical studies, in combination with image analysis, have shown that glucose-6-phosphatase is present in liver and kidney and also in specific cell types in a variety of human tissues, for example Leydig cells in the testis and some astrocytes in the brain. Where practicable, enzymatic analysis, direct transport assays and/or immunological detection of the endoplasmic reticulum glucose and phosphate transport proteins have been used to demonstrate the presence and activity of the whole glucose-6-phosphatase system. The distribution of the human glucose-6-phosphatase system changes dramatically during development with a different spatial and temporal pattern in each tissue. The most unexpected localization was in circulating, predominantly nucleated, embryonic and early fetal red blood cells.

Glucose-6-Phosphatase↗

PubMed1993

Defective neutrophil and monocyte functions in glycogen storage disease type Ib: a literature review.

A summary review of leukocyte function in 42 published cases of glycogen storage disease Ib is presented. Polymorphonuclear and monocyte dysfunctions were evidenced in the majority of cases, whereas lymphocytes appeared to be unaffected. Phagocyte dysfunctions comprised in vivo mobilization and motility, in vitro random and directed migration, and one or several component functions of the "metabolic" ("respiratory") burst. On the basis of the available data it is impossible to know whether a primary functional deficit of the glucose 6-phosphate transport protein of the microsomal glucose 6-phosphatase system, as demonstrated in liver, also exists in these phagocytic cells and is responsible for this dysfunction.

Glucose-6-Phosphatase↗