LYSOZYME

From Big Medical Encyclopedia

LYSOZYME (KF 3.2.11.17) — the enzyme catalyzing hydrolysis >a beta (1 — 4) - a glycosidic linkage between N-atsetilmuramovoy acid and N-atsetilglyukozaminom in a molecule of a peptidoglikan of a cell wall of bacteria (especially gram-positive), than causes their dissolution (lysis) and death, creating thereby an antibacterial barrier in an organism. L. is in the lacrimal liquid, mucous membranes of respiratory tracts and intestines, a phlegm, skin, milk, kidneys, a cartilage, a liver, heart, semen and blood serum of the person. In the medical practician L. apply as an antiseptic agent. Definition of activity of L. in biol, liquids use in the diagnostic purposes, in particular for diagnosis of leukemia, nek-ry diseases of kidneys (a glomerulonephritis, a nephrotic syndrome, etc.). At malignant tumors of urinogenital bodies in urine and in blood serum activity of L increases., what is used as one of tests for differential diagnosis of these diseases.

L. it is applied also in the food industry to conservation of nek-ry food stuffs.

L. contains in fabrics of various bodies and biol, liquids of the vast majority of animal organisms and in many plants, and also in nek-ry microorganisms.

For the first time it was found in 1922 by A. Fleming in protein of egg. After L. found almost in all fabrics and biol, liquids of the person. At the person L are richest. (in on 1 kg of weight) leukocytes — 10 and tears — 7, are less rich saliva — 0,2, milk — apprx. 0,04, a placenta — 0,02, a blood plasma — 0,01. From plants in the most significant amount of L. contains in turnip, horse-radish, a radish, cabbage and nek-ry flowers (e.g., in flowers of a primrose). L. it is found in bacteria (e.g., in you. subtilis), and also in bacteriophages (see) what, apparently, their bactericidal action is connected with.

In the USSR the first basic research of L. 3 were carried out. V. Ermolyeva with group of employees.

In fabrics of animal L. it is localized in lysosomes (see). In intercellular substance and in biol, liquids L. macrophages cosecrete, and from them it is allocated to 80 — 90% of total quantity

of L. L. which is contained in them from various sources differs on amino-acid structure a little. Molecule L. represents the polypeptide chain consisting of 127 — 130 amino-acid remains. N-trailer amino acid in a molecule L. is lysine (see), on the C-end of a chain is leucine (see). High content arginine (see) and lysine, dominance of free NH 2 - groups over COOH groups gives L. main character: it Isoelectric point (see) is between pH 10,5 and 11,0.

Molecule L. contains four S-S-communications, there are no free SH-group in a lysozyme.

Pier. weight (weight) of L., allocated from various sources, fluctuates over a wide range. So, pier. weight (weight) of L. makes of protein of egg apprx. 14 000, turnips — 25 000, and L., allocated from you. subtilis, has a pier. the weight (weight) apprx. 93 000. The lysozymes of animal origin allocated from different sources have a pier. the weight (weight) apprx. 15 000 (from 13 000 to 18 000).

L. let's dissolve in water at pH 4,0 — 6,0, it is quite stable at acid pH. So, solution L. in 2% solution acetic to - you maintain heating to 100 ° within 45 min. while neutral and alkaline solutions L. during the heating quickly lose enzymatic activity. L. it is quite steady against effect of proteolytic enzymes, in particular against trypsin and papain. Pepsin splits L., but with a small speed; ions of nek-ry metals (e.g., Mn 2+ ) increase resistance of L. to proteinases. L. loses activity during the blocking of free NH 2 groups and COOH-group, and also aliphatic OH-group. Inactivation of L. causes also binding of amide guanidinovy groups. It is established that in manifestation of enzymatic activity of L., in particular in formation of a fermentsubstratny complex, an essential role is played by the rest of tryptophane. It is shown also that the lysozyme for hydrolysis of a glycosidic linkage needs cooperative interaction of the rest glutaminic to - you, holding in a peptide chain of enzyme position 35, and the rest asparaginic to - you, being in the 52nd situation.

The purified drugs L. receive it adsorption on bentonite clay with the subsequent elution by pyridine or on ion-exchange resins (see. Ionites ). Crystal L. it can be received by sedimentation of 5% of NaCl in the range of pH values from 3,5 to 11,0 (from solutions L. in high-capacity buffer solutions or directly from ovalbumin). The form of crystals depends on pH of the environment. The Soviet researchers N. A. Cherkasov, N. A. Kravchenko and E. D. Kaverzneva offered a bystry method of receiving the cleared L., based on its biospecific adsorption by chitin.

Specific ability of L. to dissolve bacterial cells (usually Micrococcus lysodeikticus) is a basis of a quantitative method of definition of activity of this enzyme.

A lysozyme as drug

For use as medicine L. receive from protein of eggs.

Drug L. represents white amorphous powder or porous weight with a slight smell acetic to - you. It we will difficult dissolve in water, it is almost insoluble in alcohol; pH of 2% of solution L. 3,5 — 5,0.

L. as medicine shows antibacterial (sometimes bacteriostatic) action (see. Bacteriolysis ), suppresses growth of gram-positive microbes, gram-negative bacteria are less sensitive to it. It is very effective in a combination with antibiotics, especially penicillinic group, strengthening their action in tens of times, L. has noticeable antiheparin activity.

Apply L. at the septic conditions, purulent processes, burns, injuries, freezing injuries, conjunctivitis, erosion of a cornea, antritises and other diseases caused by L, sensitive to action. microorganisms.

Apply L. locally and intramusculary. Before use contents of a bottle with L. dissolve in 2 — 3 ml of isotonic solution of sodium of chloride or 0,25% of solution of novocaine.

Intramusculary enter 150 mg 2 — 3 times a day within not less than 7 days. If necessary the drug can be administered within 1 month.

Locally L. apply in eye practice in the form of 0,25% of solution, to-ry dig in in a sore eye 3 — 4 times a day within 3 — 7 days. In otorhinolaryngological practice apply aerosols of 0,05% of solution L. on 10 ml on a session, a course of treatment of 5 — 10 days.

At treatment of burns, freezing injuries and purulent wounds on the struck place impose napkins, the moistened 0,05% solution L.

Drugs L. are almost non-toxical, do not possess local irritative action. Drug is usually well transferred. At long intramuscular introduction it is necessary to control coagulability of blood.

Form of release: hermetically the corked bottles containing 50, 100 and 150 mg of a lysozyme.

Storage in the dry, protected from light place at a temperature not higher than 20 degrees.



Bibliography: Proteins, under the editorship of G. Neyrat and K. Bailey, lane with English, t. 1, page 13, M., 1956, t. 3, page 760, M., 1958; Bukharin O. V. and Vasilyev N. B. A lysozyme and its role in biology and the medytsena, Tomsk, 1974, bibliogr.; Ermolyeva 3. Century and d river. Experimental studying and clinical use of a lysozyme, Antibiotics, t. 8, No. 1, page 39, 1963; L of and-@-m and B. G. N, To and r and m and N about in and K. A. and Ermolyev 3. B. Use of a lysozyme in medicine, Owls. medical, No. 11, page 34, 1971, bibliogr.; Cherkasov N. A., Kravchenko N. A. and Kaverzneva E. D. About hromatografichesky behavior of a lysozyme on a column with chitin, Dokl. Academy of Sciences of the USSR, t. 170, No. 1, page 213, 1966.


L. V. Pavlikhina; V. K. Lepakhin (pharm.).

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