Nucleophilic behavior of lysine-501 of the alpha-polypeptide of sodium and potassium ion activated adenosinetriphosphatase consistent with a role in binding adenosine triphosphate

Journal Article · Tue Apr 04 04:00:00 EDT 1989 · Biochemistry; (United States)

OSTI ID:5703098

Xu, K Y; Kyte, J

An immunoadsorbent specific for the carboxy-terminal sequence -GAPER, which comprises residues 502-506 of the alpha-polypeptide of ovine sodium and potassium ion activated adenosinetriphosphatase ((Na+ + K+)-ATPase), was used to isolate the products of the reaction between the lysine immediately preceding this sequence in the intact protein and either (3H)acetic anhydride or fluorescein 5'-isothiocyanate. Changes in the apparent nucleophilicity of this lysine, Lys501, were observed with both reagents when ATP was bound by the intact, native enzyme poised in the E1 conformation or when the structure of the enzyme was changed from the E1 conformation into the E2-P conformation. With both reagents, a decrease of more than 4-fold in the yield of incorporation occurred during the former change, but a decrease of only 2-fold occurred during the latter. Because a much larger decrease occurred when ATP was bound in the absence of a conformational change than occurred when a major conformational change took place in the absence of the occupation of the active site, these changes in the incorporation of (3H)acetyl suggest that Lys501 from the alpha polypeptide is directly involved in binding ATP within the active site of (Na+ + K+)-ATPase. The immunochemical reactions between the specific polyclonal antibodies raised against the sequence-GAPER and denatured or enzymically active (Na+ + K+)-ATPase were also investigated. Western blots and the inhibition of enzymic activity caused by the antibody have shown that it can bind to both the denatured and the native form of the alpha-polypeptide, respectively.

• Research Organization: Univ. of California, San Diego, La Jolla (USA)
• OSTI ID: 5703098
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 28:7; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
AMINO ACID SEQUENCE
AMINO ACIDS
ANIMALS
ATP
ATP-ASE
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL FUNCTIONS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DOGS
ENZYME ACTIVITY
ENZYMES
FUNCTIONS
GLOBULINS
HYDROLASES
IMMUNOGLOBULINS
ISOTOPE APPLICATIONS
KIDNEYS
KINETICS
LABELLED COMPOUNDS
LYSINE
MAMMALS
MEMBRANE PROTEINS
MICROSOMES
MOLECULAR STRUCTURE
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PEPTIDE HYDROLASES
PEPTIDES
PHOSPHOHYDROLASES
POLYPEPTIDES
PROTEINS
REACTION KINETICS
REAGENTS
RECEPTORS
RIBOSOMES
SERINE PROTEINASES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TRYPSIN
VERTEBRATES