Showing papers in "Biochemical Journal in 1940"

The production of amines by bacteria: The production of tyramine by Streptococcus faecalis.

Abstract: IN the first paper of this series, the author [Gale, 1940] showed that washed suspensions of Bact. coli will decarboxylate 1( + )-arginine, 1( + )-lysine, l(+)-ornithine, 1(-)-histidine and l(+)-glutamic acid to form agmatine, cadaverine, putrescine, histamine and y-aminobutyric acid respectively. Of 14 strains of coliform organisms investigated, 12 decarboxylated arginine, 12 histidine, 13 lysine, 12 ornithine and 9 glutamic acid. The decarboxylases involved proved to be very thermolabile and were formed more easily in organisms grown at 27 than in those grown at 37°. The decarboxylase activity of the organisms was shown to depend upon the pH of the medium during growth: organisms grown at pH 7 have little decarboxylase activity but this is greatly increased (20-100-fold) by growing the organisms at pH 5. In most cases the activities were also increased by the presence of glucose in the growth medium but this increase in activity is due to the fall in pH produced during growth by the fermentation acids. The decarboxylases are active over a very restricted pH range, the optimum value in each case being: for arginine, 4 0; lysine, 4-5; histidine, 4 0; ornithine, 5 0 and glutamic acid, 4*0. None of the strains investigated decarboxylated any of the common amino-acids, other than the five mentioned, under the experimental conditions used. Emerson [1902] showed the presence of tyramine in autolysing pancreas, while Rosenheim [1909] and Barger & Walpole [1909] showed it to be one of the main pressor substances in placental extracts and putrefying meat respectively. Sasaki [1914] obtained tyramine from a medium of salts, tyrosine and glycerol heavily inoculated with Bact. coli and incubated, while Hanke & Koessler [1924] obtained this amine by the growth of pure cultures of organisms isolated from the intestine in synthetic media containing tyrosine, salts, glycerol and lactose. As a result of their investigations they suggest that organisms producing histamine are incapable of forming tyramine and vice versa. The present communication deals with the production of tyramine from tyrosine by washed suspensions of Strep. faecalis and describes the properties of the tyrosine decarboxylase present in certain strains of that organism.

The isolation of a-oestradiol and oestrone from horse testes

Abstract: ZONDEK [1934] reported the preparation of crude alcoholic eXtracts of horse testes which possessed a marked oestrogenic potency. Extracts obtained in this way were three hundred times as active oestrogenically as those prepared from a similar weight of mares' ovaries. The high oestrogenic potency of horse testes extracts has been confirmed by later workers. The present investigation was undertaken in order to isolate and identify the oestrogens responsible. A crude alcoholic extract from 28 kg. of horse testes was generously placed at the disposal of the author by Dr A. S. Parkes. This extract was concentrated, in vacuo, the acetone-insoluble material was removed and the acetonesoluble fraction was saponified by refluxing with alcoholic NaOH. The greater part of the oestrogenic activity of the inmitial concentrate appeared in the alkalisoluble, saponifiable material. That part carried over into the non-saponifiable fraction was recovered by solvent partition. Following the partitioning of the saponifiable fraction between suitable solvents, the concentrate obtained was dissolved in NaOH and -the pH was adjusted to 9 0. Ether extraction gave a \"phenolic\" fraction, which on further solvent partition gave 112 mg. of \"phenols\" possessing practically all the oestrogenic activity of the original \"saps\". These \"phenols\" were separated into ketones and non-ketones with Girard's reagent-T. Oestrone was isolated from the ketonic material as the 3:5-dinitrobenzoate (M.P. 188-191° alone or 188-192' when mixed with authentic oestrone 3:5dinitrobenzoate of M.P. 193-1940). The parent substance (M.P. 238-245°) had the same order of biological activity as authentic oestrone. x-Oestradiol was isolated from the non-ketones, following digitonin precipitation-, as its di-oc-naphthoate which melted at 1940 alone or when mixed with authentic a-oestradiol di-a-naphthoate (M.P. 1940).

Studies on diffusing factors: The action of testicular extracts on the viscosity of vitreous humour preparations

Abstract: CHAIN & DUTHIE [1939] have recently shown that testicular extracts contain an enzyme capable of hydrolysing the mucins of synovial fluid and vitreous humour. Mucinases of a similar type have been obtained from pneumococci [Dubos, 1937; Meyer et al. 1937] and from haemolytic streptococci [Meyer, 1938]. Since the first visible effect of the testicular enzyme on the mucins examined was to reduce their viscosity and since there is histological evidence for the existence of a mucin-like interfibrillar substance in skin [Bensley, 1934; Sylven, 1938], Chain & Duthie suggested that the diffusing factor and the mucinase in testicular extracts might be identical. This view is in accordance with their similarity in properties and their common occurrence in testicle and some bacterial filtrates. Ifwe are to consider the characteristic effect produced by diffusing factors as being due to enzyme action in the skin it is reasonable to assume that the increased spread of injected fluids is due to the ease with which they diffuse through tissues rendered less viscous by the action of the enzyme. Apart from mucinases other enzymes which might affect the viscosity of skin constituents are the proteases which can liquefy gelatin; it has, however, been shown [Madinaveitia, 1940] that in Cl. Welchii ifitrates at least, the proteases can be separated from the diffusing factor. It is not yet known whether testicular extracts contain a single mucolytic enzyme or a polysaccharase and an oligosaccharase. In the latter case the increase in the reducing properties of the substrate brought about by the extract would be a measure of the combined effect of the enzymes; the decrease in viscosity would be a measure of the polysaccharase activity only and, incidentally, a measure of the diffusing factor activity should it prove that the diffusing factor is indeed identical with the mucinase. The decrease in viscosity of a mucin by the action of a mucinase is a catalytic process and the disappearance of the viscous material should obey the laws of a unimolecular reaction. It has been experimentally confirmed, using testicular mucinase, that the reaction constant is independent of the substrate concentration (Table 1) and that the half-life time of a given amount of viscous substrate is inversely proportional to the concentration of the enzyme with which it reacts (Table 2). The substrate used was an acetone powder of bovine vitreous humour. The viscosity of its aqueous solutions is greatly affected by salts. Addition of small amounts of salts causes the viscosity to fall to a minimum; on further addition the viscosity again rises, the increase being parallel to that produced by adding salts to water alone. Based on these observations a viscosimetric method has been developed for the determination of mucinases. A 1 % solution of vitreous humour in a buffered M NaCl solution is allowed to react with a measured amount of enzyme solution. The time required to reduce the specific viscosity Qf the reacting mixture to half its original value is inversely proportional to the amount of enzyme used.