Interference of phenothiazine compounds in the colorimetric determination of inorganic phosphate

El-Dorry, Hamza F.A.; Medina, Heitor; Bacila, Metry

doi:10.1016/0003-2697(72)90126-1

Cited by 3 publications

(2 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the pancreatic ribonuclease converts the cyclic phosphates to the nucleoside 3'-monophosphate or hydrolyzes the dinucleoside monophosphates, the phosphatase releases the phosphate from the nucleoside monophosphate. However, in preliminary experiments, it was found that some of the Ncontaining heterocyclic compounds (e.g., chloroquine and primaquine) form a precipitate with the phosphomolybdate complex in a manner similar to other heterocyclic compounds [6,7]. Therefore, the orthophosphate was assayed by the procedure of Roufogalis [6] which results in the precipitation of heterocyclic compounds with silicotungstic acid before the determination of inorganic phosphate.…”

Section: Assuy Of Hydrolysis By Pancreatic Ribonuclease Of Low-molecumentioning

confidence: 99%

Effect of Nucleic‐Acid‐Binding Compounds on the Hydrolytic Activity of Various Ribonucleases

Holbrook

Whichard

Washington

1975

European Journal of Biochemistry

View full text Add to dashboard Cite

Studies were conducted on the stimulatory effect that various nucleic-acid-binding compounds have on the hydrolysis of RNA and polyribonucleotides by pancreatic ribonuclease A and by other ribonucleases. The stimulatory activity of chloroquine on tRNA hydrolysis by pancreatic ribonuclease was due to the formation of oligonucleotides of a wide range of sizes and was not due to the formation of very short (n > 5) oligonucleotide fragments of tRNA. The dextrorotatory and levorotatory isomers of chloroquine did not differ in their ability to stimulate the hydrolysis of tRNA by pancreatic ribonuclease A. In addition to chloroquine and primaquine, other nucleicacid-binding compounds (e.g., quinacrine, lucanthone, and proflavin) stimulated the hydrolysis of tRNA by pancreatic ribonuclease A. Chloroquine did not alter the rate of hydrolysis by pancreatic ribonuclease A of low-molecular-weight substrates (cytidine cyclic 2' : 3'-monophosphate, uridine cyclic 2': 3'-monophosphate, cytidylyl-adenosine, or uridylyl-uridine). Furthermore, chloroquine and primaquine did not affect the hydrolysis of poly(A) by high concentrations of pancreatic ribonuclease A. In studies on the hydrolysis of tRNA by other endoribonucleases, several of the nucleic-acid-binding compounds (e.g., quinacrine and ethidium) exhibited appreciable inhibition of both ribonuclease N, and ribonuclease T,. None of the compounds tested stimulated the activity of ribonuclease TI, and only chloroquine, and perhaps lucanthone, stimulated the hydrolysis of tRNA by ribonuclease N,.The interaction of various nucleic-acid-binding compounds with DNA results in a decreased enzymic hydrolysis by nucleases. In contrast, however, several nucleic-acid-binding compounds (noted for their biological activity as antimalarial drugs) stimulate the activity of two endoribonucleases, namely pancreatic ribonuclease A and micrococcal nuclease, against tRNA and various polyribonucleotides Various studies have been conducted on the effects of nucleic-acid-binding compounds on RNA synAbbreviations. Cyd-2': 3'-P, cytidine cyclic 2': 3'-monophosphate; Urd-2': 3'-P, uridine cyclic 2': 3'-monophosphate; CpA, cytidylyl-adenosine ; UpU, uridylyl-uridine.Enzymes. Pancreatic ribonuclease or ribonucleate pyrimidinenucleotido-2'-transferase (cyclizing) (EC 3.1.4.22) ; micrococcal nuclease or ribonucleate (deoxyribonucleate) 3'-nucleotidohydrolase (EC 3.1.4.7); guanyloribonucleases (namely ribonucleases N1 and TI) or ribonucleate guaninenucleotide-2'-transferase (cyclking) (EC 3.1.4.8).thesis and function (ie.. protein synthesis). Since it is anticipated that the potential stimulation of endogenous ribonucleases in cellular systems in vitro might markedly affect the experimental results in studies of RNA or protein synthesis, a more detailed examination was made of the increased nuclease activity which can be elicited by these compounds. It is found that, in addition to the aminoquinolines, a number of other N-heterocyclic, nucleic-acid-binding compounds stimulate the hydrolysis of RNA by sever...

show abstract

Section: Assuy Of Hydrolysis By Pancreatic Ribonuclease Of Low-molecumentioning

confidence: 99%

Effect of Nucleic‐Acid‐Binding Compounds on the Hydrolytic Activity of Various Ribonucleases

Holbrook

Whichard

Washington

1975

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

“…Inorganic phosphate released in the reaction was measured as in [ 15]. No interference of phenothiazines, when tested at various concentrations, during colorimetric determination of phosphate was found [16]. Ultracentrifugation studies were performed on a MSE Centriscan 75, at a rotor speed of 60 000 rev/min and temp.…”

Section: Methodsmentioning

confidence: 99%