Carnosinase activity of human gastrointestinal mucosa
Laboratory studyHumansOther animals
- Design
- Laboratory study
- Subjects
- Human mucosal samples: 15 patients with histologically normal mucosa and 5 with villous atrophy for the jejunal activity comparison; coeliac patients followed on a gluten-free diet (number not stated in abstract); one patient with carnosinase deficiency for tolerance tests. Rat gut tissue also assayed.
- Dose used in the study
- not applicable (enzyme assay); carnosine tolerance tests in one patient, amount not stated in abstract
- Duration
- not stated in abstract
- What was measured
- Carnosinase (the dipeptidase that hydrolyses carnosine and other histidine-containing dipeptides) activity in mucosal tissue of the human and rat gut by region, its kinetic properties, its change with mucosal healing in coeliac disease, and oral tolerance curves for carnosine versus its constituent amino acids in one carnosinase-deficient patient.
What the authors reported
Carnosinase activity was found in small-intestinal mucosa with kinetic properties similar to the enzyme from other animal tissues. Little or no activity was detected in gastric or colonic mucosa, and duodenal activity was lower than jejunal, a distribution the authors describe as similar to the disaccharidases. Mean jejunal activity was 8.8 units per g in 15 patients with normal mucosa versus 5.7 units in 5 with villous atrophy, and activity rose as coeliac mucosa improved on a gluten-free diet. Tolerance curves showed malabsorption of the dipeptide in a carnosinase-deficient patient, and the authors conclude that the mucosa hydrolyses carnosine much more slowly than glycylglycine and other dipeptides, so hydrolysis appears to be the rate-limiting step in its absorption.
Limits of this study
Small patient numbers, a single carnosinase-deficient case for the absorption observation, and a 1975 assay method. Units of activity are reported as units per g of tissue without further definition in the abstract. Findings relate to mucosal enzyme activity, not to serum carnosinase or to supplement dosing. Full text not read.
Source
PubMed 1237444 · doi:10.1136/gut.16.8.585
Entry checked against PubMed abstract (E-utilities) on 2026-10-19. The dose shown is the dose the researchers used. It is not a recommendation. How to read this page.