[Professor Jakub Karol Parnas: 140th birth anniversary].

In 2024, it will be 140 years since the birth of Jan Karol Parnas, one of the most outstanding biochemists and one of the most outstanding Polish scientists of the first half of the 20th century. The article presents a synthetic biography of Prof. Parnas, his influence on the organization of scientific life in interwar Poland, and presents his students and collaborators who created the so-called "The School of Parnassus".

Structural studies of human muscle FBPase.

Muscle fructose-1,6-bisphosphatase (FBPase), which catalyzes the hydrolysis of fructose-1,6-bisphosphate (F1,6BP) to fructose-6-phosphate (F6P) and inorganic phosphate, regulates glucose homeostasis by controlling the glyconeogenic pathway. FBPase requires divalent cations, such as Mg2+, Mn2+, or Zn2+, for its catalytic activity; however, calcium ions inhibit the muscle isoform of FBPase by interrupting the movement of the catalytic loop. It has been shown that residue E69 in this loop plays a key role in the sensitivity of muscle FBPase towards calcium ions.

T-to-R switch of muscle fructose-1,6-bisphosphatase involves fundamental changes of secondary and quaternary structure.

Fructose-1,6-bisphosphatase (FBPase) catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and is a key enzyme of gluconeogenesis and glyconeogenesis and, more generally, of the control of energy metabolism and glucose homeostasis. Vertebrates, and notably Homo sapiens, express two FBPase isoforms. The liver isozyme is expressed mainly in gluconeogenic organs, where it functions as a regulator of glucose synthesis.

The mechanism of calcium-induced inhibition of muscle fructose 1,6-bisphosphatase and destabilization of glyconeogenic complex.

The mechanism by which calcium inhibits the activity of muscle fructose 1,6-bisphosphatase (FBPase) and destabilizes its interaction with aldolase, regulating glycogen synthesis from non-carbohydrates in skeletal muscle is poorly understood. In the current paper, we demonstrate evidence that Ca(2+) affects conformation of the catalytic loop 52-72 of muscle FBPase and inhibits its activity by competing with activatory divalent cations, e.g.

A comparative study on the sensitivity of Cyprinus carpio muscle and liver FBPase toward AMP and calcium.

The activity of fructose-1,6-bisphosphatase (FBPase; EC 3.1.3.