Triaminotricarboxylic amino acid oxidation productions of actinoidin and ristomycin]

Aromatic acids with three benzene nuclei bound through oxygen were obtained from actinoidin and ristomycin on their oxydation with permanganates of methylated aglycones and peptides. The structures of the methyl esters of these acids were determined by spectral methods. They are the following: methyl-3,5-bis-(4-methoxycarbonyl-phenoxy)-4-methoxybenzoate (from ristomycin) and methyl-3-(2-chlor-4-methoxycarbonyl-phenoxy)-5-(4-methoxycarbonyl-phenoxy)-4-methoxybenzoate (from actinoidin). The compounds are the aromatic parts of the molecules of the unusual triaminotricarboxylic amino acids present in the aglycones of all antibiotics of the group of polycyclic glycopeptides.     

New amino acid from the antibiotic, ristomycin A]

A new amino acid E was isolated from a mixture of the products of the reductive hydrolysis of ristomycin A 57% HJ in the presence of red phosphorus. Its characterization was performed. The new amino acid was formed as a result of reductive dehydration of the respective beta-oxyamino acid present in the native antibiotic and being completely destroyed during general acid or alkaline hydrolysis.     

Isolation and study of the physicochemical properties of the partial acid hydrolysis products of the aglycone actinoidin]

Two new fragments, i.e. products I and II were found in the process of studying the products of acid hydrolysis of actinoidin aglycone. Both compounds were isolated in the form of homogenous preparations by the method of ion exchange chromatography on cellulose KM. Their physico-chemical properties and element composition were studied. It was found that product I was phenylalanine dipeptide (Phe) and oxyaromatic triamiotricarboxylic compound (Y) not described earlier, while product II was tripeptide including diaminodicarboxylic actinoidinic amino acid (B) in addition to phenylalanine and fragment Y.     

Amino acid makeup, structural characteristics and substrate specificity of rabbit plasma kininogen]

Highly purified kininogen preparation with the activity of 16-18 int. units per mg was isolated from rabbit blood serum. Its molecular weight was estimated to be 54 000 by gel filtration through Sephadex G-200. Leucine was identified as N-terminal amino acid by the dansylation method. Rabbit kininogen consists of 394 amino acid residues (except tryptophane). Amino acid composition of kininogen is characterized by a high content of dicarbonic amino acids, proline and by a low content of methionine. Kininogen molecule does not contain SH-groups. 13.1-13.5 SH-groups were found in kininogen after the reduction of S-S bonds with beta-mercaptoethanol in the presence of 8 M urea, thus indicating the presence of 6-7 S-S bonds in kininogen molecule. Kininogen group does not occupy C-terminal position in the molecule, because the treatment of the protein with carboxypeptidase B does not change the content of bradykinine in it. Purified kininogen preparation is a substrate for kallikrein from rabbit blood plasma, human saliva and trypsin. Unlike trypsin, kallikreines from human blood plasma and saliva release kinines from kininogen with reduced S-S bonds. Under spontaneous reoxidation of reduced S-S bonds up to 90%, substate properties of kininogen for tripsin recover only by 50%. Rabbit kininogen is similar to beef kininogen II in its molecular weight, amino acid composition and the number of S-S bonds.     

Fatty acid makeup of various Brucella species and its relationship to the culture medium]

Gas chromatographic method was applied to the study of the fatty acid composition (in Br. melitensis, Br. abortus, Br. suis, and Br. ovis strains. Fatty acid composition was similar in the mentioned brucellae species, except Br. suis No. 1330 significantly differing by this sign. Methyleneoctadecanoic acid content was considerably elevated, and that of octadecenoic -- reduced in brucellae grown on liver agar with the addition of serum and on meat-peptone agar in comparison with brucellae grown on liver agar; apparently this represents one of the mechanisms of the microorganism adaptation to the less favourable conditions of the nutrient medium. Passage of Br. ovis strain through the guinea pig organism led to the appearance of brucellae forming two types of colonies when grown on liver agar with the addition of serum. The fatty acid composition of brucellae forming small transparent colonies was the same as that of the initial culture with the prevalence of methyleneoctadecanoic acid; as to brucellae with larger colonies with irregular margin and nontransparent centre of the colony--octadecenoic acid prevailed in their fatty acid composition, i.e. their composition was similar to such in brucellae of the melitensis and abortus species grown on liver agar.     

Fatty acid makeup of the lipids in soil and epiphytic yeasts]

The fatty acid composition of lipids was compared among yeast cultures belonging to the genera Rhodotorula, Lipomyces, and Cryptococcus. These lipids contain C10--C26 fatty acids, mainly with the even number of carbon atoms. Palmitic acid (C16 : 0) and oleic acid (C18 : 0) predominate. In the majority of the strains, the sum of unsaturated acids exceeds the sum of saturated acids. The content of unsaturated acids in the lipids of the epiphytic yeast Rhodotorula is higher than in the soil yeast Lipomyces. Besides C12--C18 acids, C22--C26 acids were identified by GLC at preset temperatures. Lignoceric acid (C24 : 0) was found for the first time in the cultures of Rhodotorula, Lipomyces, and Cryptococcus, and cerotinic acid (C16 : 0) was also detected in the Rhodotorula yeast. Fatty acids with a long chain are registered in the strains of Rhodotorula more often than in the strains of Lipomyces and Cryptococcus.     

Fluorometric-colorimetric amino acid analysis of actinomycins using fluorescamine. Mechanism of partial threonine decomposition during acid hydrolysis.

a fluorometric-colorimetric fluorescamine analyzer was successfully utilized for the analysis of a series of actinomycin hydrolysates containing N-methyl-amino acids, proline, and proline derivatives. An explanation is proposed for the low threonine values consistently observed in the analysis of actinomycin hydrolysates and alternate conditions for improved hydrolysis of actinomycins are proposed.     

Fatty acid makeup of the cestodes, Eubothrium crassum and Diphyllobothrium dendriticum]

The fat-acidic composition of E. crassum and D. dendriticum was investigated. Lipids of E. crassum differ in greater unsaturation as compared to these of D. dendriticum as well as in greater amount of acids of type omega 3, whereas acids of type omega 6 and stearic acid were found in extracts of E. crassum in less quantity than in D. dendriticum. This phenomenon is characteristic of organisms living under conditions of low temperatures.     

Studies on the enzymatic hydrolysis of amino acid carbamates

Several commercially available enzymes were tested for their ability to hydrolyze amino acid carbamates. No activity was found with pig liver esterase, the hydantoinase from Pseudomonas fluorescens DSM 84, or the urease from jack beans. A stereoselective cleavage of the carbamyl group yielding L-amino acids was observed by acylase and acetylcholinesterases from bovine and human erythrocytes. Racemic mixtures of N-(methoxycarbonyl)-DL-alanine, N-(ethoxycarbonyl)-DL-alanine, and the corresponding valine carbamates are hydrolyzed to L-alanine and L-valine, respectively, by acylases leaving the D-amino acid carbamates unchanged. The lysine carbamates were not hydrolyzed by acylases. In contrast only the methoxycarbonyl amino acids were split by acetylcholinesterases, which, however, also cleave alpha, epsilon-(N-methoxycarbonyl)-DL-lysine stereoselectively at the alpha position, yielding epsilon-N-methoxycarbonyl-L-lysine. The optimum pH for enzymatic activity of hog kidney acylase was 7.5 and a Km value of 8.2 mM for N-(methoxycarbonyl)-DL-alanine was determined. For the acetylcholinesterases the reaction rate reaches an optimum between pH 7.5 and 8. The Km value was 68 mM for N-(methoxycarbonyl)-DL-alanine.