phosphorylase kinase

Phosphorylase Kinase β-Subunit Fragment (420-436) is a peptide fragment (430-436) derived from the β-Subunit of phosphorylase kinase. Phosphorylase kinase, a serine/threonine-specific protein kinase, plays a crucial role in activating glycogen phosphorylase for the release of glucose-1-phosphate from glycogen [1].

K-252a is a protein kinase inhibitor targeting serine-threonine, tyrosine, and CAM kinases. In vitro, it blocks NGF-induced TrkA signalling and neural differentiation, exhibiting antitumour, antibacterial, anti-inflammatory, and neuroprotective activities.

Staurosporine (AM-2282) is a protein kinase inhibitor with ATP-competitive and non-selective inhibitory activity (IC50=6/15/2/3/3000 nM) against PKC, PKA, c-Fgr, phosphorylase kinase and TAOK2. Staurosporine also induces apoptosis.

Disodium monofluorophosphate (NSC248) is a competitive inhibitor of pyruvate kinase and alkaline phosphatase, which also irreversibly inhibits phosphorylase phosphatase.

N6-Methyladenosine 5'-monophosphate disodium salt is a glycogen phosphorylase b activator and an inhibitor of adenylate kinase II.

7-oxo Staurosporine is an antibiotic originally isolated from S. platensis with diverse biological activites. It inhibits PKC, PKA, phosphorylase kinase, EGFR, and c-Src in vitro (IC50s = 9, 26, 5, 200, and 800 nM, respectively). 7-oxo Staurosporine induces cell cycle arrest in the G2/M phase in human leukemia K562 cells with a minimal effective dose (MED) of 30 ng/ml. It is cytotoxic to P388 mouse leukemia cells that are resistant and susceptible to doxorubicin . 7-oxo Staurosporine inhibits growth of the mycelial, but not yeast form of C. albicans, C. krusei, C. tropicalis, and C. lusitaniae (MICs = 3.1-25 μg/ml). It increases sphingomyelin synthesis in CHO-K1 cells when used at a concentration of 50 nM.

The cyanobacterium Nodularia spumigena often contaminates the drinking water of rural communities in developing countries and accumulates in mussels, flounder, and cod from the northern Baltic Sea. Nodularin is a hepatotoxic monocylic pentapeptide produced by the N. spumigena. It is a potent inhibitor of protein phosphatase types 1 (PP1) and 2A (PP2A), exhibiting IC50 values of 1.8 and 0.026 nM, respectively. PP2B is inhibited to a lesser extent with an IC50 of 1.8 μM. No apparent inhibitory effect is observed with PP2C, alkaline phosphatase, acid phosphatase, insulin receptor tyrosine kinase, protein kinase A, phosphorylase kinase, or protein kinase C.

5-Iodotubercidin (NSC-113939) is a potent adenosine kinase inhibitor with IC50 of 26 nM. It inhibits nucleoside transporter, CK1, insulin receptor tyrosine kinase, phosphorylase kinase, PKA, CK2 and PKC.

Malantide TFA, a synthetic dodecapeptide, originates from the phosphorylation site targeted by cAMP-dependent protein kinase (PKA) on the β-subunit of phosphorylase kinase. Exhibiting a high specificity for PKA with a Michaelis constant (Km) of 15 μM, this compound demonstrates more than 90% inhibition of substrate phosphorylation in the presence of protein inhibitor (PKI) across various rat tissue extracts [1]. Moreover, Malantide TFA acts as an effective substrate for Protein Kinase C (PKC) with a Km of 16 μM [2].

Myelin Basic Protein (MHP4-14) TFA, a synthetic peptide comprising residues 4-14 of myelin basic protein, serves as a highly selective substrate for protein kinase C (PKC) with a K_m of 7 μM. It is not phosphorylated by cyclic AMP-dependent protein kinase, casein kinases I and II, Ca^2+/calmodulin-dependent protein kinase II, or phosphorylase kinase, making it an ideal candidate for protein kinase C assays in crude tissue extracts, ensuring minimal background interference [1] [2].

Rp-Adenosine-5'-O-(1-thiodiphosphate) (Rp-ADP-α-S), a sulfur-containing isomer of the nucleotide derivative ADP-α-S, acts as an inhibitor of phosphorylase kinase with an inhibition constant (Ki) of 0.53 µM. This compound also induces aggregation in isolated human platelets with an effective concentration (EC50) of 20 µM and promotes relaxation in guinea pig taenia coli that has been precontracted with carbamoylcholine, with an EC50 of 58.9 µM.

Sp-Adenosine-5'-O-(1-thiodiphosphate) (Sp-ADP-α-S), an isomer of the sulfur-containing nucleotide derivative ADP-α-S, functions as an inhibitor of phosphorylase kinase with an inhibition constant (Ki) of 0.53 µM. This compound also promotes aggregation of isolated human platelets with an effective concentration (EC50) of 20 µM and induces relaxation in carbamoylcholine-precontracted guinea pig taenia coli with an EC50 of 58.9 µM.