PHOSPHAGENS

From Big Medical Encyclopedia

PHOSPHAGENS (synonym: guanidiifos-veils, N-fosforilguanidiny) — you-sokoergichesky natural soyedino-niya, the representing fosforilirovanny derivatives of guanidines. T. meet in tissues of animals and the person, especially there are a lot of them in skeletal muscles where F. serve add l ny not tochn and a lump

of energy for muscular work (see). To number F. phosphoryl iro-vainy derivative creatine (see) — creatine phosphate belongs (a synonym: fosfokreatia, to reatinfosfo rny to - that, N - phosphorus pl-to re at AI, N - fosfo r silt mt silt of at and and ides in-at ks a mustache of a share to - that), characteristic for che-

a loveka p vertebrate animals. Fosfoamidinovy communication (N ~ P) in a molecule F. it is hydrolyzed with allocation of energy (see Vysokoergichesky connections).

The most known F. backboneless animals phosphoarginine is (a synonym: phosphoarginine, phosphoarginine to - that, N-fosforilarginin, N-fosforilguanidinamino-valerian to - that):


T. represent kisl from the labile connections which are hydrolyzed in the subacidic environment at 30 — 37 °. Salts of creatine phosphate and phosphoarginine well of a rastvorima in water, are insoluble in alcohol. Definition F. as a part of protein-free fabric extracts, and also T., received in a stand-at-ease, it is based on measurement of amount of the inorganic phosphate emitted at their hydrolysis and the corresponding guanidinovy connection. Creatine phosphate in the presence of acid solution of ammonium molybdate turns into creatinine, quantity to-rogo determine by staining reaction with picric to - that (Jaffe's reaction).

In a human body and animals F. are synthesized by means of specific to everyone F. kinases (ATP: guanidinephosphotransferases),

catalyzing transfer of trailer phosphate — at - ATP phosphate on guanidinovy connection (see Kinases). The most studied enzymes participating in transformation F., are a creatine kinase (ATP: N-fosfotransferaza creatine; KF

2.7.3.2) and arginine kinase (ATP: L-arginine] \tsh-phosphotransferase; KF

2.7.3.3). The creatine kinase (see) received in a high cleaning state from skeletal muscles and also from a myocardium, tissue of a brain and other bodies and body tissues of the person and vertebrate animals, catalyzes reversible transfer of the phosphatic (fosforilny) rest from creatine phosphate on ADF:


The ratio between amount of creatine and creatine phosphate in muscular tissue depends from fiziol. conditions of muscles. At muscular contraction (see) when access of oxygen is complicated, synthesis of ATP in a cell is provided to hl. obr. due to glycolysis (see) and for regeneration of ATP in the working muscle creatine phosphate is used. At rest


there is an accumulation of ATP due to oxidizing phosphorylation (see biological oxidation) and the creatine kinase catalyzes synthesis of creatine phosphate. Concentration of creatine phosphate in the based muscle is 3 — 8 times higher, than concentration of ATP, and quantity of it F. there is enough to support a fixed level of ATP in a muscle cell at a big functional load of a muscle. As an end product of exchange of creatine phosphate serves creatinine (1-metilglikotsiamidin). Creatinine is always present at urine where its quantity varies, but is more or less constant for each person; it is expressed by a so-called creatinine coefficient (see Creatine). At the pathology connected with a muscular atrophy (see the Atrophy muscular), the disturbance of phosphorylation of creatine leading to the increased allocation with urine of creatine and to reduction of amount of the emitted creatinine is observed (see the Creatinuria). The creatinuria which is followed usually by increase in activity of a creatine kinase in serum and a blood plasma in clinic is one of diagnostic characters of various forms of a muscular atrophy, a myocardial infarction and other diseases.

Bibliography: Berezov T. T. and To

rovkin B. F. Biological chemistry, M., 1982; Lyzlova S. N. Phosphagen kinase, JI., 1974; Moss D. V. and B and P. J. Enzimologiya's t-tervort and medicine, the lane with English, M., 1978; Whyte A., etc. Fundamentals of biochemistry, the lane with English, t. 1 — 3, M., 1981; The enzymes, ed. by P. D. Boyer, y. 8, p. 383, 457, N. Y., 1973, bibliogr. P.JI. Vulfson.

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