There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

The goal of this review is to present a comprehensive survey of the many intriguing facets of creatine (Cr) and creatinine metabolism, encompassing the pathways and regulation of Cr biosynthesis an...

http://www.afboard.com/library/creatinemetabolism.pdf

Creatine and Creatinine Metabolism

Mathematica--A System for Doing Mathematics by Computer.

Arginase is a primordial enzyme, widely distributed in the biosphere and represented in all primary kingdoms. It plays a critical role in the hepatic metabolism of most higher organisms as a cardinal component of the urea cycle. Additionally, it occurs in numerous organisms and tissues where there is no functioning urea cycle. Many extrahepatic tissues have been shown to contain a second form of arginase, closely related to the hepatic enzyme but encoded by a distinct gene or genes and involved in a host of physiological roles. A variety of functions has been proposed for the “extrahepatic” arginases over the last three decades. In recent years, interest in arginase has been stimulated by a demonstrated involvement in the metabolism of the ubiquitous and multifaceted molecule nitric oxide. Molecular biology has begun to furnish new clues to the disparate functions of arginases in different environments and organisms. Comparative studies of arginase sequences are also beginning to elucidate the comparative evolution of arginases, their molecular structures and the nature of their catalytic mechanism. Further studies have sought to clarify the involvement of arginase in human disease. This review presents an outline of the current state of arginase research by giving a comparative overview of arginases and their associated properties.

Comparative properties of arginases.

Production of Nitric Oxide by Mitochondria

We propose that, in the cell, the reversible conversion of actin filaments into actin bundles is controlled by the concentration of the macromolecules [we have employed poly(ethylene glycol) 6000 to mimic the macromolecules of the cell] as well as by the nature of the ancillary cytoskeletal proteins that decorate actin filaments. The proposal is based on the following evidence. (1) Under our experimental conditions the transition from filaments into bundles occurs at increasing concentrations of poly(ethylene glycol), with the following sequence: caldesmon-actin, 3%; filamin-actin, 4-5%; caldesmon-tropomyosin-actin, 5-7%; actin, 6-7%; tropomyosin-actin, 9-10%. (2) Under conditions of low osmoelastic stress [3% poly(ethylene glycol)], preformed caldesmon-actin bundles are dissociated by the addition of either tropomyosin or tropomyosin-decorated actin. The dissociation of the bundles promoted by the addition of tropomyosin-decorated actin is faster than that promoted by the addition of tropomyosin.

/pdf/macromolecular-crowding-is-a-primary-factor-in-the-60x8i3bx7n.pdf

'Macromolecular crowding' is a primary factor in the organization of the cytoskeleton.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2875%2980966-5

On the biosynthesis of creatine. Intramitochondrial localization of transamidinase from rat kidney.

Arginases have been found to be located on the external side of the inner mitochondrial membrane of chicken kidney and liver.



Transamidinase has been detected within the liver mitochondrial matrix space.



Arginases and transamidinase act upon two different intracellular arginine pools.



Penetration of arginine into the matrix space occurs only in respiring mitochondria and in the presence of anions such as acetate and phosphate; d-arginine, l-ornithine, d-ornithine and l-lysine penetrate with the same modalities. l-Histidine penetrates only kidney mitochondria.



Because of transamidinase compartmentation, the rate of creatine synthesis is influenced by the rate of penetration of arginine into the mitochondria.

On the control of arginine metabolism in chicken kidney and liver.

The diameter of the actin filament decreases with an increase of the protein osmotic pressure. This phenomenon is accompanied by a decrease of the angle (a) formed between the long axis of the actin monomer and the pointed end of the filament axis. At 1.8 x lo5 dyn/cm2 (the protein osmotic pressure in frog muscle) the diameter is 8.34 nm and the angle (a) is 61.5'. The interfilament distance of tropomyosin-decorated actin filaments, at a set of different osmotic pressures, is larger than that of F-actin filaments. This suggests that the two tropomyosin helices project out of the contour of the actin filament. The tropomyosin-decorated actin filament is more rigid than F-actin. At 1.8 x lo5 dyn/cm2, the angle (a) is 76.4", as compared to the value of 61.5" for F-actin. The interfilament distance of troponin- tropomyosin-decorated actin filaments is sensitive to Ca2+: in the physiological range of protein osmotic pressure it decreases from 13.3 nm, in the presence of 2 mM EGTA, to 12.2 nm in the presence of 0.2 mM CaC12. Two alternative models are proposed to explain the decrease in interfilament distance. (a) Calcium shifts tropomyosin along the actin monomer, toward the filament axis (the classical model). (b) Calcium releases the rigidity of the tropomyosin-decorated filament and restores the original plasticity of F-actin. The consequent decrease of the angle (a) brings the tropomyosin helices nearer to the filament axis, without any real movement of tropomyosin along the actin monomer.

Osmotic Properties of the Calcium-Regulated Actin Filament?

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2879%2980833-9

Ermes Magri

Papers

'Macromolecular crowding' is a primary factor in the organization of the cytoskeleton.

On the biosynthesis of creatine. Intramitochondrial localization of transamidinase from rat kidney.

On the control of arginine metabolism in chicken kidney and liver.

Osmotic Properties of the Calcium-Regulated Actin Filament?

Phosphorylation of actin and removal of its inhibitory activity on pancreatic DNAase I by liver plasma membranes