Similarities and differences in the properties of multiple isoforms of maize endosperm casein kinase I (CK-I)

Two novel type I casein kinases named CK-1B and CK-1C have been purified from maize endosperm (three weeks after anthesis) by a six step procedure involving ammonium sulfate precipitation, DEAE-cellulose, Sephadex G-75, Heparin-sepharose, and ATP-agarose chromatography. The catalytic subunits of both enzymes were identified as a 35-37 kDa polypeptide doublet by in situ phosphorylation after SDS/PAGE in active casein gel. Both enzymes required 5-10 mmol · L⁻¹ Mg²⁺ for maximal activity, could utilize only ATP as phosphate donor, were insensitive to heparin, were not autophosphorylated, had a pH optimum at pH 7 to 8.5, and exclusively phosphorylated acidic proteins (casein, phosvitin). Regarding the enzyme differences, their properties were as follows: a) CK-1B could bind on ATP-agarose affinity column, while CK-1C could not; b) the activity of CK-1C was strongly stimulated at low concentrations (1 mmol/L) of spermine, while that of CK-1B was inhibited; c) CK-1B and CK-1C Km values for ATP were 11 μmol · L⁻¹ and 26 μmol · L⁻¹, respectively; d) Mg²⁺ could substituted by Mn²⁺ in the CK-1B catalytic activity (by about 80 percnt;); e) CK-1B phosphorylated serine, while CK-1C both serine and threonine on casein. The combination of these results with those from Babatsikos and Yupsanis (2000) brings the number of investigated maize endosperm CK-I isoforms to three (CK-1B, CK-1C, and CK-1E). This is the first biochemical approach demonstrating that multiple isoforms of CK-I casein kinases are present in the same plant tissue.     

Carotenogenesis in Phycomyces

Time course studies of carotenoid production and of mycelial growth in liquid cultures of Phycomyces blakesleeanus wild type [NRRL 1555 (?)], red mutants C9, C10 and C13 and the heterokaryon C2 * C9 are reported. The ratios of the concentrations of lycopene, γ-carotene and β-carotene in the red mutant C13 and in the heterokaryon C2 * C9 during the growth periods were measured. In these strains the concentration of lycopene is close to its final value after 2 days of growth, at a time at which β-carotene is just beginning to be produced. It is suggested that the β-carotene produced late is possibly synthesized via β-zeacarotene.     

Phytochrome control of oscillating levels of phenylalanine ammonia lyase in Hordeum vulgare shoots

Five-day-old etiolated barley shoots respond to brief illumination with red light by increasing their level of PAL ca 50% within 5 hr. When assayed s     

Synthesis of novel Schiff bases and azol-β-lactam derivatives starting from morpholine and thiomorpholine and investigation of their antitubercular,antiurease activity,acethylcolinesterase inhibition effect and antioxidant capacity

In this study, new Schiff bases and β-lactam derivatives containing morpholine and thio morpholine nuclei were synthesized. Antimicrobial, antioxidant, antimicrobial and antioxidant properties of all synthesized compounds were investigated and highly effective products were obtained. In this context, new effective structures were introduced to the literature.     

New carboxamides bearing benzenesulphonamides: Synthesis,molecular docking and pharmacological properties

Ten new derivatives of benzenesulphonamide bearing carboxamide functionality were synthesized and investigated for their in vitro antimicrobial, antioxidant and in vivo anti-inflammatory activities. Compound 9d inhibited carrageenan induced rat-paw oedema at 93.81, 88.79 and 86.09% at 1 h, 2 h and 3 h administration respectively. In the antimicrobial activity, compound 9a (6.54, 6.69 and 6.64 mg/mL) was most potent against S. aureus, B. subtilis and C. albicans respectively, compound 9e (6.45 and 6.46 mg/mL) was most active against P. aeruginosa and A. niger respectively while compound 9i (6.24 mg/mL) was most active against E. coli. Only compound 9a (IC₅₀ 0.3052 mg/mL) had comparable activity with Vitamin C (IC₅₀ 0.2090 mg/mL) in the antioxidant assay.     

Thymidine kinase isoenzymes in human acute monocytic leukemia

Summary Two thymidine kinase isoenzymes, TK 3 and TK 4, from mononuclear leucocytes from a patient with acute monocytic leukemia, were purified and characterized in regard to the molecular weights and kinetic properties.The molecular weights of TK 3 and TK 4 were 60 000 and 45 000, respectively. In the presence of 2 mM ATP, the molecular weight of TK 3 increased to 200 000, whereas the molecular weight of TK 4 was unchanged.Studies of the kinetic properties showed clear differences between TK 3 and TK 4. With thymidine as substrate, TK 3 showed biphasic kinetics with a K_m of 22 µM, and TK 4 showed Michaelis-Menten kinetics with a K_m of 0.33 µM With ATP as substrate, TK 3 showed Michaelis-Menten kinetics with a K_m of 100 µM, and TK 4 showed biphasic kinetics with a Km of 3.5 µM. With dTTP as inhibitor, TK 3 showed cooperative inhibition kinetics, and TK 4 showed non-cooperative competitive inhibition kinetics. The dTTP concentration at 50% inhibition was 75 µM for TK 3 but 380 µM for TK 4.Comparison of the molecular weights and the kinetic properties of TK 3 and TK 4 with the corresponding data previously obtained for TK 1 and TK 2 from normal human lymphocytes indicate the existence of four thymidine kinase isoenzymes in human leucocytes.     

Metrics from nonlinear dynamics adapted for characterizing the behavior of nonequilibrium enzymatic rate functions

Several metrics from nonlinear dynamics and statistical mechanics have been characterized on computer-generated number series with various signal-to-noise ratios, demonstrating their individual reliability as a function of sample size and their relationships to each other. The root mean square (RMS) evaluates amplitude, and the power spectral density (PSD) provides a visual display of the frequency spectrum; both measures have very high reliability even for an N as low as 50. The Fractal Dimension (D) is shown to converge rapidly and also to be reliable when N is as low as 50. These three measures (RMS, PSD, and D) have been applied to the complex kinetics of tyrosine hydroxylase time courses (50-point curves) at various BH4 concentrations (near physiological, but far from equilibrium levels). Recently developed measures of spectral entropy and the Liapunov Exponent, -lambda are also characterized.     

Combinatorial array-based enzymatic polyester synthesis.

A combinatorial strategy for biocatalytic polymer synthesis is demonstrated. A library of polymers was synthesized in 96 deep-well plates using AA-BB polycondensations of acyl donors and acceptors. The library was based on four straight-chain diesters as acyl donors (C(3)-C(10)) with aliphatic/aromatic diols as well as more diverse structures including carbohydrates, nucleic acids, and a natural steroid diol used as acyl acceptors. The lipase from Candida antarctica was active in acetonitrile and was capable of catalyzing the polycondensation of the aforementioned monomers to polymers with M(w)'s reaching as high as 20,000 Da, including the preparation of novel sugar-containing polyesters. The combinatorial approach to biocatalytic polymer synthesis described herein serves as a foundation for polymeric materials discovery by demonstrating that polymer arrays can be produced from structurally complex monomers.     

Investigation on the effect of alkyl chain linked mono-thioureas as Jack bean urease inhibitors,SAR, pharmacokinetics ADMET parameters and molecular docking studies

The increasing resistance of pathogens to common antibiotics, as well as the need to control urease activity to improve the yield of soil nitrogen fertilization in agricultural applications, has stimulated the development of novel classes of molecules that target urease as an enzyme. In this context, the newly developed compounds on the basis of 1-heptanoyl-3-arylthiourea family were evaluated for Jack bean urease enzyme inhibition activity to validate their role as potent inhibitors of this enzyme. 1-Heptanoyl-3-arylthioureas were obtained in excellent yield and characterized through spectral and elemental analysis. All the compounds displayed remarkable potency against urease inhibition as compared to thiourea standard. It was found that novel compounds fulfill the criteria of drug-likeness by obeying Lipinski’s rule of five. Particularly compound 4a and 4c can serve as lead molecules in 4D (drug designing discovery and development). Kinetic mechanism and molecular docking studies also carried out to delineate the mode of inhibition and binding affinity of the molecules.