Identification, purification, characterization and regulation of the rabbit peritoneal neutrophil cytosolic inositol 1,4,5-trisphosphate 5-phosphomonoesterase

Thesis/Dissertation · Fri Jan 01 00:00:00 EST 1988

OSTI ID:7105705

Kennedy, S P

Inositol 1,4,5-trisphosphate (IP{sub 3}) is a second messenger involved in intracellular Ca{sup 2+} mobilization. Its enzymatic breakdown by inositol 1,4,5-trisphosphate 5-phosphomonoesterase (IP{sub 3} phosphatase) yields inositol 1,4-bisphosphate (IP{sub 2}) which does not mobilize Ca{sup 2+}. Thus, the IP{sub 3} phosphatase can serve to regulate internal free Ca{sup 2+} levels. In Triton X-100 permeabilized rabbit peritoneal neutrophils and neutrophil cytosol, exogenously added ({sup 3}H)IP{sub 3} is rapidly hydrolyzed to IP{sub 2}, inositol monophosphate (IP) and free inositol. The rate of IP{sub 3} hydrolysis was greater than that of IP{sub 2} in permeabilized neutrophils, while the converse was observed in cytosol. DE-52 chromatography of cytosol separates the specific from nonspecific IP{sub 3} phosphatase activity. Further purification of the specific enzyme resulted in a 790-fold purification over cytosol activity, however, the IP{sub 3} phosphatase could not be identified with any protein in this preparation. The neutrophil IP{sub 3} phosphatase has a molecular weight of 43-47 kDa, and an isoelectric point of 5.6, as determined by size exclusion chromatography and Chromatofocusing, respectively. Physiological concentrations of Ca{sup 2+} and calmodulin have no effect on IP{sub 3} phosphatase activity. Activation of endogenous protein kinase C in permeabilized cells and cytosol also has no effect on the activity. Characteristics of the neutrophil IP{sub 3} phosphatase are discussed in relation to IP{sub 3} phosphatases in other cells and tissues.

• Research Organization: Connecticut Univ., Storrs, CT (USA)
• OSTI ID: 7105705
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOSPHATASES
CHEMICAL COMPOSITION
CHROMATOGRAPHY
ENZYME ACTIVITY
FRACTIONATION
MOLECULAR WEIGHT
NEUTROPHILS
PERITONEUM
RABBITS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
ENZYMES
ESTERASES
HYDROGEN COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
LEUKOCYTES
MAMMALS
MATERIALS
MEMBRANES
SEPARATION PROCESSES
SEROUS MEMBRANES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques