K-252a, a novel microbial product, inhibits smooth muscle myosin light chain kinase

Journal Article · Thu May 05 00:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:7076237

Nakanishi, S; Yamada, K; Kase, H; Nakamura, S; Nonomura, Y

Effects of K-252a, purified from the culture broth of Nocardiopsis sp., on the activity of myosin (light chain kinase were investigated. 1) K-252a affected three characteristic properties of chicken gizzard myosin-B, natural actomyosin, to a similar degree: the Ca/sup 2 +/-dependent activity of ATPase, superprecipitation, and the phosphorylation of the myosin light chain. 2) K-252a inhibited the activities of the purified myosin light chain kinase and a Ca/sup 2 +/-independent form of the enzyme which was constructed by cross-linking of myosin light chain kinase and calmodulin using glutaraldehyde. The degrees of inhibition by 3 x 10/sup -6/ M K-252a were 69 and 48% of the control activities with the purified enzyme and the cross-linked complex, respectively. Chlorpromazine (3 x 10/sup -4/ M), a calmodulin antagonist, inhibited the native enzyme, but not the cross-linked one. These results suggested that K-252a inhibited myosin light chain kinase by direct interaction with the enzyme, whereas chlorpromazine suppressed the enzyme activation by interacting with calmodulin. 3) The inhibition by K-252a of the cross-linked kinase was affected by the concentration of ATP, a phosphate donor. The concentration causing 50% inhibition was two orders magnitude lowere in the presence of 100 ..mu..M ATP than in the presence of 2 mM ATP. 4) Kinetic analyses using (..gamma..-/sup 32/P)ATP indicated that the inhibitory mode of K-252a was competitive with respect to ATP. These results suggest that K-252a interacts at the ATP-binding domain of myosin light chain kinase.

• Research Organization: Kyowa Hakko Kogyo Co., Ltd., Tokyo (Japan)
• OSTI ID: 7076237
• Journal Information: J. Biol. Chem.; (United States), Vol. 263:13
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ENZYME INHIBITORS
BIOCHEMICAL REACTION KINETICS
MYOSIN
PHOSPHORYLATION
PHOSPHOTRANSFERASES
INHIBITION
ATP
ATP-ASE
CHLORPROMAZINE
ELECTROPHORESIS
MUSCLES
PHOSPHORUS 32
ACID ANHYDRASES
AMINES
AZINES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CENTRAL NERVOUS SYSTEM AGENTS
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYMES
GLOBULINS
HETEROCYCLIC COMPOUNDS
HYDROLASES
HYPNOTICS AND SEDATIVES
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHENOTHIAZINES
PHOSPHOHYDROLASES
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PROTEINS
PSYCHOTROPIC DRUGS
RADIOISOTOPES
REACTION KINETICS
TRANQUILIZERS
TRANSFERASES
550201* - Biochemistry- Tracer Techniques