Wyniki wyszukiwania

1

A biomimetic approach to some specifically functionalized cyclic terpenoids

100%

Kulcitki V.

Acta Biochimica Polonica

|

2007

|

tom 54

|

nr 4

679-693

The paper relates on the current advancements in the synthesis of complex cyclic terpenoids by superacidic induced cyclization of open chain precursors. It is shown that functional groups disposal in the initial substrate strongly influences the reaction outcome. Possible variations of the investigated compound structures include particularly α-functionalization and α,ω-bifunctionalization. This approach allowed a selective initiation of cyclization sequence from an internal double bond or suspending the ring closure cascade to partially cyclized compounds. The reported synthetic schemes are attempts to mimic the biogenetical processes postulated in the living systems.

2

Importance of intramolecular protein dynamics to kinetics of biochemical processes

100%

Kurzynski M.

Cellular and Molecular Biology Letters

|

1999

|

tom 04

|

nr 1

Several points seem essential for construction of the future statistical theory of biochemical processes. (a) The native proteins involved in these processes reveal a purely stochastic intramolecular dynamics of conformational transitions much slower than the usual vibrational dynamics. At least in the range from 10-11 to 10-7s the relaxation time spectrum of conformational transition dynamics is practically quasi-continuous. (b) The majority of reactions involving proteins are controlled and, presumably, also gated by this stochastic dynamics. (c) Of special importance is the short initial-condition dependent stage of biochemical reactions, neglected in the description of the reaction in terms of the standard kinetics. This stage is directly observed in experiments in which especially prepared initial conformational substates of the protein are confined to the reaction transition state. (d) The initial-condition dependent stage, and not that described by the standard kinetics, is responsible for the coupling of component reactions in the complete catalytic cycles proceeding in the steady-state and more complex processes of biological free energy transduction.

3

Lipid-binding proteins as stabilizers of membrane microdomains - possible physiological significance

70%

Bandorowicz-Pikula J.

Acta Biochimica Polonica

|

2000

|

tom 47

|

nr 3

Below the melting point temperature of lipids, artificial lipid membranes usually exist in the ordered gel phase. Above these temperatures lipid acyl chains become fluid and disordered (liquid-crystalline phase). Depending on the chemical composition of artificial membranes, phase separation may occur, leading to the formation of transient or stable membrane domains. A similar phase separation of lipids into ordered and disordered domains has been observed in natural membranes at physiological temperature range. Moreover, it has been reported that certain proteins prefer certain organization of lipids, as for example glycosylphosphatidylinositol-anchored proteins or Src family of tyrosine kinases. The aim of present review is to discuss the possibility that some lipid microdomains are induced or stabilized by lipid-binding proteins that under certain conditions, for example due to a rise of cytosolic Ca2+ or pH changes, may attach to the membrane surface, inducing clustering of lipid molecules and creation of ordered lipid microdomains. These domains may than attract other cytosolic proteins, either enzymes or regulatory proteins. It is, therefore, postulated that lipid microdomains play important roles within a cell, in signal transduction and enzymatic catalysis, and also in various pathological states, as Alzheimer's disease, anti-phosphatidylserine syndrome, or development of multidrug resistance of cancer cells.

Ograniczanie wyników

2 Acta Biochimica Polonica

1 Cellular and Molecular Biology Letters

1 Bandorowicz-Pikula J.

1 Kulcitki V.

1 Kurzynski M.

1 2007

1 2000

1 1999

A biomimetic approach to some specifically functionalized cyclic terpenoids

Importance of intramolecular protein dynamics to kinetics of biochemical processes

Lipid-binding proteins as stabilizers of membrane microdomains - possible physiological significance