Influence of Regeneration of Reduced Triphosphopyridine Nucleotide (TPN) on Formation of cis-Polyisoprene in Hevea Brasiliensis

1965 ◽  
Vol 38 (2) ◽  
pp. 450-451
Author(s):  
Daniel Ribaillier ◽  
Tuong Chi Cuong ◽  
Paul Fournier

Abstract Hevea brasiliensis latex can use glucose-6-phosphate to produce triphospho-pyridine nucleotide and adenosine triphosphate. Conversion of sodium acetate and mevalonic acid depends on the presence of these cofactors.

Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 500-506 ◽  
Author(s):  
CR Zerez ◽  
MD Wong ◽  
NA Lachant ◽  
KR Tanaka

Abstract RBCs from patients with hemolytic anemia due to pyruvate kinase (PK) deficiency are characterized by a decreased total adenine and pyridine nucleotide content. Because phosphoribosylpyrophosphate (PRPP) is a precursor of both adenine and pyridine nucleotides, we investigated the ability of intact PK-deficient RBCs to accumulate PRPP. The rate of PRPP formation in normal RBCs (n = 11) was 2.89 +/- 0.80 nmol/min.mL RBCs. In contrast, the rate of PRPP formation in PK-deficient RBCs (n = 4) was markedly impaired at 1.03 +/- 0.39 nmol/min.mL RBCs. Impaired PRPP formation in these cells was not due to the higher proportion of reticulocytes. To study the mechanism of impaired PRPP formation, PK deficiency was simulated by incubating normal RBCs with fluoride. In normal RBCs, fluoride inhibited PRPP formation, caused adenosine triphosphate (ATP) depletion, prevented 2,3-diphosphoglycerate (DPG) depletion, and inhibited pentose phosphate shunt (PPS) activity. These results together with other data suggest that impaired PRPP formation is mediated by changes in ATP and DPG concentration, which lead to decreased PPS and perhaps decreased hexokinase and PRPP synthetase activities. Impaired PRPP formation may be a mechanism for the decreased adenine and pyridine nucleotide content in PK-deficient RBCs.


Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 500-506
Author(s):  
CR Zerez ◽  
MD Wong ◽  
NA Lachant ◽  
KR Tanaka

RBCs from patients with hemolytic anemia due to pyruvate kinase (PK) deficiency are characterized by a decreased total adenine and pyridine nucleotide content. Because phosphoribosylpyrophosphate (PRPP) is a precursor of both adenine and pyridine nucleotides, we investigated the ability of intact PK-deficient RBCs to accumulate PRPP. The rate of PRPP formation in normal RBCs (n = 11) was 2.89 +/- 0.80 nmol/min.mL RBCs. In contrast, the rate of PRPP formation in PK-deficient RBCs (n = 4) was markedly impaired at 1.03 +/- 0.39 nmol/min.mL RBCs. Impaired PRPP formation in these cells was not due to the higher proportion of reticulocytes. To study the mechanism of impaired PRPP formation, PK deficiency was simulated by incubating normal RBCs with fluoride. In normal RBCs, fluoride inhibited PRPP formation, caused adenosine triphosphate (ATP) depletion, prevented 2,3-diphosphoglycerate (DPG) depletion, and inhibited pentose phosphate shunt (PPS) activity. These results together with other data suggest that impaired PRPP formation is mediated by changes in ATP and DPG concentration, which lead to decreased PPS and perhaps decreased hexokinase and PRPP synthetase activities. Impaired PRPP formation may be a mechanism for the decreased adenine and pyridine nucleotide content in PK-deficient RBCs.


Nature ◽  
1958 ◽  
Vol 182 (4636) ◽  
pp. 662-663 ◽  
Author(s):  
G. B. BARLOW ◽  
A. D. PATRICK

1978 ◽  
Vol 31 (12) ◽  
pp. 2751 ◽  
Author(s):  
AC Finlayson ◽  
RH Prager

Benzoic acid[14CO2H] and sodium acetate[2-14C] are incorporated into 4- methoxy-2-phenylquinoline,the major alkaloid in the leaves of L. amara. No radioactivity is found in the quinoline when sodium acetate[1-14C] or phenylalanine[3-14C] are administered; this suggests the alkaloid is derived from anthranilic acid by the pathway suggested by Leete.1 Mevalonic acid[2-14C] is incorporated into the furanoquinoline alkaloid lunacrine.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


Sign in / Sign up

Export Citation Format

Share Document