Phosphorylation of the sarcoplasmic calcium-activated adenosinetriphosphatase as studied by /sup 31/P nuclear magnetic resonance

Journal Article · Tue May 19 04:00:00 EDT 1987 · Biochemistry; (United States)

OSTI ID:5720931

Sontheimer, G M; Kalbitzer, H R; Hasselbach, W

A reinvestigation of a study in which the /sup 31/P nuclear magnetic resonance (NMR) signal of the phosphointermediate of the sarcoplasmic (Ca/sup 2 +/, Mg/sup 2 +/)-ATPase has been identified shows that the signal described most probably originates from free Mg x ATP but not from the phosphoenzyme itself. It was possible to detect the /sup 31/P NMR signal of the phosphoenzyme in peptic fragments of sarcoplasmic ATPase phosphorylated either by ATP or by inorganic phosphate. The two products exhibit the same spectral characteristics in /sup 31/P NMR, implying that most probably both reaction pathways yield the same chemical product. Chemical shifts at low pH (-6.5 ppm) and high pH (-1.4 ppm) of the phosphoryl group are indicative of a ..beta..-phosphoaspartyl moiety, thus confirming independently the results from chemical analysis. The relatively low pK value of 4.3 of the phosphoryl group suggests an interaction with a positively charged group of the enzyme.

• Research Organization: Max Planck Institute for Medical Research, Heidelberg, West Germany
• OSTI ID: 5720931
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:10; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ACID ANHYDRASES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
ATP-ASE
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CATIONS
CELL CONSTITUENTS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMICAL SHIFT
CHLORIDES
CHLORINE COMPOUNDS
ENZYMES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
IONS
ISOTOPES
LIGHT NUCLEI
MAGNESIUM CHLORIDES
MAGNESIUM COMPOUNDS
MAGNETIC RESONANCE
MAMMALS
MUSCLES
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANOIDS
PH VALUE
PHOSPHOHYDROLASES
PHOSPHORUS 31
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
RABBITS
RESONANCE
SARCOPLASMIC RETICULUM
STABLE ISOTOPES
VERTEBRATES