Correction of Cobalamin Malabsorption in Pancreatic Insufficiency with a Cobalamin Analogue that Binds with High Affinity to R Protein but not to Intrinsic Factor: IN VIVO EVIDENCE THAT A FAILURE TO PARTIALLY DEGRADE R PROTEIN IS RESPONSIBLE FOR COBALAMIN MALABSORPTION IN PANCREATIC INSUFFICIENCY
AUTOR(ES)
Allen, Robert H.
RESUMO
In vitro studies indicate that [57Co]cobalamin (Cbl) is preferentially bound to salivary R protein as opposed to intrinsic factor (IF) and that [57Co]Cbl bound to R protein is not transferred to IF at either pH 2 or pH 8. Incubation of R protein-[57Co]Cbl with pancreatic proteases causes a partial degradation of the R protein moiety and a rapid transfer of [57Co]Cbl to IF. We have postulated that the etiology of Cbl malabsorption in pancreatic insufficiency is an inability to partially degrade R protein because of a lack of pancreatic proteases. We have tested this hypothesis by determining the ability of a nonradioactive Cbl analogue, bound with high affinity by R protein but not by IF, to correct the malabsorption of [57Co]Cbl in patients with pancreatic insufficiency.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372689Documentos Relacionados
- Effect of Proteolytic Enzymes on the Binding of Cobalamin to R Protein and Intrinsic Factor: IN VITRO EVIDENCE THAT A FAILURE TO PARTIALLY DEGRADER PROTEIN IS RESPONSIBLE FOR COBALAMIN MALABSORPTION IN PANCREATIC INSUFFICIENCY
- Cobalamin malabsorption due to nondegradation of R proteins in the human intestine. Inhibited cobalamin absorption in exocrine pancreatic dysfunction.
- Cobalamin malabsorption in three siblings due to an abnormal intrinsic factor that is markedly susceptible to acid and proteolysis.
- Malabsorption of hemoglobin iron in pernicious anemia: correction with intrinsic factor—containing substances
- Evidence that POB1, a Saccharomyces cerevisiae protein that binds to DNA polymerase alpha, acts in DNA metabolism in vivo.