Identification of a third form of NaK-ATPase catalytic subunit in rat brain by photoaffinity labeling

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6173395

Lowndes, J M; Millan, N M; Ruoho, A E; Hokin-Neaverson, M

Using photoaffinity labeling, they have found a form of the NaK-ATPase catalytic subunit, ..cap alpha..(-), in the rat brain that is distinct from the ..cap alpha.. and ..cap alpha..(+) forms. Strong radiolabeling of ..cap alpha..(-) was obtained with (/sup 125/I)azido-iodophenethylamido-succinyl-cymarin (AISC). AISC is a new cardiotonic steroid photolabel which they have synthesized and characterized chemically and biochemically. This compound labels ..cap alpha..(-) better than the photolabels that they have previously reported. SDS-PAGE (5%) of photolabeled rat brain microsomes showed that ..cap alpha..(-) migrated with faster mobility than the dog kidney ..cap alpha.. subunit. The ..cap alpha..(-) appears to have different specificity for different cardiotonic steroids than either ..cap alpha..(+) or ..cap alpha... The radiolabeling of rat brain ..cap alpha..(+) and dog kidney ..cap alpha.. with (/sup 125/I)AISC was protectable by ouabain; in contrast, 1 mM ouabain did not reduce the (/sup 125/I)AISC-labeling of ..cap alpha..(-), although the labeling was protected with 200 ..mu..M cymarin or AISC. The results indicate that the ..cap alpha..(-) form of the NaK-ATPase in rat brain binds cymarin and its derivative but has little affinity for ouabain. It is possible that ..cap alpha..(-) may be the translation product of the rat brain ..cap alpha..(III) mRNA which has recently been described.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 6173395
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
AFFINITY
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
HYDROLASES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLING
MAMMALS
MICROSOMES
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PHOSPHOHYDROLASES
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
SPECIFICITY
STEROIDS
TRACER TECHNIQUES
VERTEBRATES