Nov 1, 1976

gamma-glutamyl transpeptidase of rat intestine: localization and possible role in amino acid transport

T Q GarveyK J Isselbacher


gamma-Glutamyl transpeptidase (gamma-GT), an enzyme possibly involved in amino acid transport, was investigated in rat small intestine using the synthetic substrate L-gamma-glutamyl-p-nitroanilide. Enzyme localization and characteristics were correlated with features of amino acid uptake. gamma-GT activity copurified with sucrase and alkaline phosphatase. Activity was maximal at pH 8.2 and was stimulated by monovalent cations. The relative specificity of the gamma-GT reaction with diglycine and eight essential amino acids as substrates correlated well with the rate of intestinal absorption of this dipeptide and these amino acids as observed by others. gamma-GT activity was 12-fold greater in the jejunum than in the ileum, again in agreement with relative rates of amino acid absorption along the length of rat intestine. The specific activity of gamma-GT in villus tip cells was 10 times greater than in crypt cells, and amino acid uptake was 2 to 6 times greater with villus tip than with crypt cells. Bromosulfophthalein, a noncompetitive inhibitor of gamma-GT, inhibited amino acid uptake. These studies support the concept that membrane gamma-GT may be involved in amino acid and dipeptide uptake, and indicate that further investiga...Continue Reading

  • References
  • Citations


  • We're still populating references for this paper, please check back later.
  • References
  • Citations


  • This paper may not have been cited yet.

Mentioned in this Paper

Establishment and Maintenance of Localization
Malignant Neoplasm of Jejunum
Tissue Viability
Amino Acids, I.V. solution additive
Gamma-glutamyl transferase
Small Intestinal Wall Tissue
Alkaline Phosphatase Measurement

About this Paper

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Bone Marrow Neoplasms

Bone Marrow Neoplasms are cancers that occur in the bone marrow. Discover the latest research on Bone Marrow Neoplasms here.

IGA Glomerulonephritis

IgA glomerulonephritis is a chronic form of glomerulonephritis characterized by deposits of predominantly Iimmunoglobin A in the mesangial area. Discover the latest research on IgA glomerulonephritis here.

Cryogenic Electron Microscopy

Cryogenic electron microscopy (Cryo-EM) allows the determination of biological macromolecules and their assemblies at a near-atomic resolution. Here is the latest research.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

LRRK2 & Immunity During Infection

Mutations in the LRRK2 gene are a risk-factor for developing Parkinson’s disease. However, LRRK2 has been shown to function as a central regulator of vesicular trafficking, infection, immunity, and inflammation. Here is the latest research on the role of this kinase on immunity during infection.

Antiphospholipid Syndrome

Antiphospholipid syndrome or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by the presence of antibodies directed against phospholipids.

Meningococcal Myelitis

Meningococcal myelitis is characterized by inflammation and myelin damage to the meninges and spinal cord. Discover the latest research on meningococcal myelitis here.

Alzheimer's Disease: MS4A

Variants within membrane-spanning 4-domains subfamily A (MS4A) gene cluster have recently been implicated in Alzheimer's disease by recent genome-wide association studies. Here is the latest research.