Author
Cyrus H. Fiske
Bio: Cyrus H. Fiske is an academic researcher from Harvard University. The author has contributed to research in topics: Urea & Phosphorus. The author has an hindex of 14, co-authored 23 publications receiving 18654 citations.
Topics: Urea, Phosphorus, Excretion, Titration, Sulfate
Papers
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18,029 citations
194 citations
TL;DR: The first very important work of SubbaRow with Fiske was to develop a rapid but accurate method for the determination of phosphorus as phosphate in biological samples, which paved the way for establishing the presence of several other biological phosphorus compounds.
Abstract: The first very important work of SubbaRow with Fiske was to develop a rapid but accurate method for the determination of phosphorus as phosphate in biological samples. It paved the way for establishing the presence of several other biological phosphorus compounds. They discovered phosphocreatine followed quickly by ATP, glycerophosphate and others. Here we have reproduced the paper wherein they have described their work on muscle ATP, a significant contribution to DNA structure, and liver glycerophosphate.
161 citations
90 citations
79 citations
Cited by
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TL;DR: If the highest accuracy was not required, the following manipulations simplified and speeded multiple total phosphorus determinations on the eluates from column chromatographic separations.
12,381 citations
7,125 citations
TL;DR: The phosphomolybdenum method is routinely applied in the laboratory to evaluate the total antioxidant capacity of plant extracts and to determine vitamin E in a variety of grains and seeds, including corn and soybean.
4,644 citations
TL;DR: Actin purified by a new, simple, and rapid purification procedure activated the ATPase activity of both heavy meromyosin and Subfragment 1 of heavy mercyosin, and this activation was not inhibited by the removal of Ca2+.
4,306 citations
TL;DR: Both the holoenzyme and the catalytic subunit (or fragment), which is active without an enzyme activator, are susceptible to these compounds with a similar concentration dependency, thereby indicating that the inhibitory effect is attributed to the direct interaction of the compound with the active center of the enzyme but not with the enzymeactivator.
Abstract: Naphthalenesulfonamides such as N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide (W-7) are potent calmodulin (CaM) antagonists and act upon several protein kinases at higher concentration. When the naphthalene ring was replaced by isoquinoline, the derivatives were no longer CaM antagonists but retained the ability to inhibit protein kinases, and some of the derivatives exhibited selective inhibition toward a certain protein kinase. cAMP-dependent, cGMP-dependent, and Ca2+-phospholipid-dependent (protein kinase C) protein kinases were inhibited significantly by addition of 10(-6) M N-[2-(methylamino)ethyl]-5-isoquinoline-sulfonamide (H-8) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7). H-8 was the most active of the inhibitors in this series and inhibited more markedly cyclic nucleotide dependent protein kinases, than other kinases, while the derivative with the sulfonylpiperazine residue (H-7) was the most potent in inhibiting protein kinase C. Apparent Ki values of H-8 were 0.48 and 1.2 microM for cGMP-dependent and cAMP-dependent protein kinases, respectively, and the Ki value of H-7 for protein kinase C was 6 microM. Both the holoenzyme and the catalytic subunit (or fragment), which is active without an enzyme activator, are susceptible to these compounds with a similar concentration dependency, thereby indicating that the inhibitory effect is attributed to the direct interaction of the compound with the active center of the enzyme but not with the enzyme activator. The inhibitions were freely reversible and of the competitive type with respect to ATP and of the noncompetitive type with respect to the phosphate acceptor.(ABSTRACT TRUNCATED AT 250 WORDS)
2,651 citations