pH-dependent glycine uptake in the presence and absence of sodium ions from rat small intestine.
Intestinal uptake of glycine in rats was stimulated 15-20% in the presence of 120 mM Na at pH 6.0 and below but around neutral pH, the amino acid uptake was augmented to 60% compared to that in the Na-free medium. Glycine uptake was 30% more at pH 5.5 compared to that at pH 7.3 in the absence of Na. Kinetic analysis revealed a decrease in Kt for glycine uptake (9.62 mM) at pH 5.5 compared to that at pH 7.3 (Kt = 16.67 mM) with no change in maximal velocity (1.51 mumole/10 min/g tissue) in Na-free buffer. Addition of -SH group reacting reagents to the incubation medium produced 36-58% inhibition of glycine uptake in the presence of Na. However, in absence of Na, inhibition of the order of 21-35% and 8-23% was observed at pH 5.5 and 7.0, respectively. These findings suggest that glycine uptake in rat intestine is influenced by pH and -SH groups are implicated in the process(es).
Kapoor
M
M
Department of Biochemistry, Panjab University, Chandigarh, India.
Babbar
H S
HS
Jaswal
V M
VM
Mahmood
A
A
D000818:Animals; D005998:Glycine / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007421:Intestine, Small / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology*; D013439:Sulfhydryl Reagents
D013439:Sulfhydryl Reagents; D012964:Sodium; D005998:Glycine