ISSN:
1432-072X
Keywords:
Crithidia fasciculata
;
Biopterin
;
D-Glucose
;
D-Galactose
;
Na+-K+-α-Naphthyl Acetic Acid
;
2,4-Dinitrophenol
;
Proton Excretion
;
Transport
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Biopterin uptake by Crithidia fasciculata is pH dependent with optimum at pH 6 and is strongly inhibited by 0.5 mM NAA and DNP,respectively. Both inhibitors also reduce respiration by 40% (NAA) and 97% (DNP). K+-ions (1.1%) and K+/Na+ (0.5% each) stimulate biopterin uptake to the same high extent, but ouabain has no effect, thereby ruling out involvement of Na+/K+ pump. In absence of these ions, even in 5% glucose solution biopterin uptake is reduced to minimum. Proton excretion seems to be linked to sugar uptake. Both these sugars seem to have the same site of entry, demonstrated by competitive uptake, though D-glucose is taken up much faster by Crithidia than D-galactose. DNP (0.5 mM) causes greater proton excretion in glucose than in galactose medium. With NAA (0.5 mM) proton excretion is inhibited in both glucose and galactose media. D-glucose promotes greater biopterin uptake than D-galactose.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00403044
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