Gel filtration of H meromyosin prepared by treatment of myosin A with trypsin [EC 3. 4. 4. 4] using Sephadex G-200 or a Bio-Gel P-300 column yields two peaks of protein fractions (Fraction 1 and 2, ATPase [EC 3. 6. 1. 3] active) which are barely separated, and a shoulder part (Fraction 3, ATPase inactive) in its elution diagram. The molecular weight was estimated as 350, 000, 160, 000 and between 100, 000 and 10, 000 for Fraction 1, 2 and 3, respectively. H meromyosin prepared with chymotrypsin [EC 3. 4. 4. 5] showed a similar elution pattern but with another peak (Fraction 2', M. W., 80, 000, ATPase active) in between Fraction 2 and 3. Fraction 2, 2' and 3 may be products of Fraction I by further digestion of proteolytic enzymes, suggesting that H meromyosin Fraction I (original H meromyosin) consists of certain num-bers of sub-unit chains which retain the ATPase activity. Helical con-tent of Fraction 1 and 2 was approximately the same and that of Fraction 2' was 1/2 of Fraction 1. Fraction 1 has strong ability to bind with actin, Fractin 2 can interact with actin but in weaker degree than that of Fraction 1. Fraction 2' has no ability to bind with actin. On partial destruction of its structure by sonic treatment, H meromyosin Fraction 1 easily loses actin binding ability before reduction of ATPase activity becomes noticeable. There is a possibility that the active center in H meromyosin for interaction with actin is constituted from the plural numbers of sub-unit chains which cooperate with each other. Thus, it is concluded that the structual elements are involved to a greater extent in the actin binding center than in the ATPase active center of H meromyosin.

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A synaptic vesicle fraction was prepared from the neocortex of guinea pig and the properties of its ATPase [EC 3. 6. 1. 3] were investigated. The following results were obtained.
1. ATP is split at a rate of 4.5μmoles/mg. protein/30 minutes at 20°C and pH 7.4 in the presence of 4.0mM Mg++, and the rate of splitting of ADP is about 20% of that of ATP. AMP does not serve as a substrate.
2. ATPase is activated about 10 fold by 4.0mM Ca⁺⁺ or 8.0mM Mg⁺⁺. The Km for Ca⁺⁺ is 4.5×10^-4M and that for Mg⁺⁺ is 1.9x10^-4M.
3. 1.0mM EDTA abolishes ATPase activity completely while 1.0mM GEDTA has only a slight inhibitory effect. 4.0mM Mg⁺⁺ and Ca⁺⁺ reverse the inhibitions caused by these chelating reagents.
4. In the absence of divalent cation, 0.10M K⁺ stimulates ATPase activity, while 0.60M K⁺ is inhibitory. The effect of Na⁺ is similar to that of K⁺. 1.0mM EDTA abolishes the effect of Na⁺ or K⁺ on ATPase activity, whereas in the presence of 1.0mM GEDTA the effect of Na⁺ or K⁺ is similar to that in the presence of Mg⁺⁺. When Mg⁺⁺ is present, the activating effect of 0.10M Na⁺ or K⁺ is not clear, but the inhibitory effect 0.60M Na⁺ or K⁺ increases.
5. Thiol blocking reagents depress ATPase activity. Glutathione and cysteine reverse the inhibition caused by these thiol blocking reagents.
6. Treatment by phospholipase C [EC 3. 1. 4. 3], freezing and thaw-ing, or 10mM desoxycholic acid depress ATPase activity.
7. There is a slight competition between Mg⁺⁺ and Ca⁺⁺. 5.0×10^-4M DNP has no effect. Oligomycin and atractylate do not decrease the activation induced by Mg⁺⁺. No reduction of cytochrome c is seen with 50mM succinic acid as substrate.
8. Na⁺ plus K⁺ stimulates ATPase slightly in the presence of Mg⁺⁺ and ouabain abolishes this effect. With a more purified synaptic vesicle preparation, however, the inhibitory effect of ouabain is incomplete.

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1. The absorption spectrum of the photo-induced semiquinone of D-amino acid oxidase [EC 1. 4. 3. 3] was calculated. The spectrum coincided with that of the dithionite reduced semiquinone.
2. The E'₀ of photo-induced semiquinone was estimated as ap-proximately -125mV. The semiquinone reduced cytochrome c in an anaerobic condition.
3. D-Amino acid oxidase combined with pyruvate or phenylpyruvate did not form the photo-induced semiquinone by irradiation under anaerobic conditions, but turned to colorless form. This colorless form was not autoxidizable and contained undecomposed flavin.

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The in vivo conversion of cholestanol and 7α-hydroxycholesterol to bile salts was studied in the carp.
1. When cholestanol-5, 6-³H was injected intraperitoneally into carp, radioactive 5α-cyprinol, 27-deoxy-5α-cyprinol and allocholic acid were isolated from the gall-bladder bile.
2. After intraperitoneal injection of 7α-hydroxycholesterol-7β-³H into carp, the metabolites excreted in the bile were shown to be 5α-cyprinol, 27-deoxy-5α-cyprinol, allocholic acid and cholic acid.

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Living hemolytic streptococci could lyre in vitro not only erythrocytes but also tumor cells, through direct contact. The cytolytic reaction was temperature dependent, inhibited by trypan blue, EDTA, arsenite, chioramphenicol or puromycin, and occurred at the maximal rate only in the presence of phosphate, Mg⁺⁺ and maltose (energy source). Like the hemolytic activity, the oncolytic activity was rather labile, and for its maintenance all the components of Bernheimer's basal medium were necessary. The inactivation of oncolytic activity was always accompanied by a loss of hemolytic activity of the bacteria, and vice versa. Both activities were detected neither in streptococci grown in a glucosebroth nor in a mutant strain C 203 U lacking CBH. From these and other results, it was concluded that there is an exceedingly close relationship between the oncolytic activity of the organisms and cell-bound streptolysin S.

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The following compounds were synthesized as analogues of ATP: Tubercidin 5'-triphosphate (II), 2', 3'-O-isopropylidene 6-chloro-(9-β-D-ribofuranosyl) purine 5'-triphosphate (III) and 2', 3'-O-isopropylidene-6-mercapto-(9-β-D-ribofuranosyl) purine 5'-triphosphate (IV). The interac-tion of these analogues with actomyosin systems, together with those of P³-methyl-adenosine 5'-triphosphate (I), were investigated.
The degrees of decrease in light-scattering of myosin B on the addi-tion of these analogues were similar to that induced by ATP, except in the case of Compound I. The rates of hydrolysis of the analogues by myosin B in 0.6M KCl and 7mM Ca⁺⁺ were in the decreasing order of ATP>IV>II>III_??_I, while the order of hydrolysis in 0.075M KCl and 2mM Mg⁺⁺ was II_??_IV>III>ATP_??_I. Compound I was not hy-drolyzed at all. Compounds II and III induced weak contraction of myofibrils, while Compounds IV and I did not.
Our present and previous results together with those of other workers on the interaction between ATP analogues and actomyosin systems were summarized. Analysis of these results has considerably clarified the roles of the three parts of ATP (the base, ribose and triphosphate) in the decrease in light-scattering of myosin B caused by ATP, the hydrolysis of ATP by the myosin-type ATPase reaction and the contraction of myofibrils induced by ATP.

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1. An Na⁺-K⁺-ATPase [EC 3. 6. 1. 3] preparation obtained from pig cerebrum microsomes by NaI-treatment has been shown to hydrolyse ATP in the presence of either K⁺ alone (K⁺-ATPase) or Nab alone (Na⁺-ATPase) when the assay pH was low for the former and high for the latter.
2. K⁺-ATPase activity had the optimum pH at 5.3 when K⁺ concentration was 1mM. Na⁺-ATPase activity was near maximum when the assay pH was between 7.7 and 9.0 at Na⁺-concentration of 10mM.
3. Ouabain-sensitive Mg⁺⁺-ATPase activity has been detected with the optimum pH which was nearly the same as that of K⁺-ATPase activity but with a pH-activity curve broader toward alkalinity than that for the latter.

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To clarify the production of 19S antibody, the incorporation of C¹⁴-amino acids into antiovalbumin antibodies was studied using various lymphoid tissues from guinea pigs which had been immunized with ovalbumin.
1. The spleen, mesenteric lymph nodes and granuloma tissues at the site of injection incorporated C¹⁴-amino acids into 19S and 7S antiovalbumin antibodies. However, the gel-filtration patterns of the antibody produced were different from tissue to tissue.
2. In all the tissues examined, the activity to synthesize the 19S antibody seemed to decrease after repeated immunization, whereas the 7S antibody production was considerably promoted.
3. In addition to the 19S and 7S components, an antibody component which seemed to be similar to human IgA was isolated from the gel-filtration of C¹⁴-labelled antiovalbumin antibody fractions produced by various lymphoid tissues.

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Two forms of porcine caeruloplasmin, designated previously as component I and component II, were separated by zone electrophoresis on cyanogum gel. The difference in enzymatic activity between components I and II could not be observed except for a slight difference in the activity using p-phenylenediamine as the substrate. Anomalies were observed in the kinetics of p-phenylenediamine oxidation. A bimolecular reaction mechanism with respect to the substrate was proposed to interprete these anomalies.

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A difference spectrum was observed between dithionite-treated liver microsomes and those treated with NADH under aerobic conditions. The difference spectrum showed two broad peaks at 445 and 555mμ and a trough at 418mμ. When microsomes were contaminated by hemoglobin, the peak at 445mμ was shifted to shorter wavelengths. The intensity of the 445mμ peak, corrected for hemoglobin, was linearly correlated to the content of P-450 in various microsomal preparations with widely varied contents of the hemoprotein. It was concluded from this and other findings that the dithionite minus NADH difference spectrum corresponds to the spectral difference between the reduced and oxidized forms of P-450. When microsomes were aged under aerobic conditions, there was a decrease in the content of P-450 and a shift of the peak at 445 to 450mμ.

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The content of Floridean starch in a calcareous red alga, Joculator maximus, was as high as approximately 3 per cent of dried fronds, and was not influenced by the season. The starch was easily isolated from the aqueous extract in a high yield by removing concomitant mucilagenous impurities with benzalkonium chloride. The [α]¹⁰_D value in water of the starch was +195.5°, and its iodine complex showed an absorption maximum at 550mμ. The starch comsumed 1.06 mole of periodate and released 0.06 mole of formic acid per anhydroglucose unit, suggesting that it contains no significant amount of 1, 3-linkage and that an average chain length is approximately 17. Methylation data also excluded the existence of 1, 3-linkage.

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1. When rats were pretreated with cortisone (5mg. daily for 5 days prior to partial hepatectomy), the increase in the DNA synthesis which would usually occur during the course of liver regeneration was greatly retarded, the induction of thymidine kinase [EC 2. 7. 1. 21] and thymidylate kinase(s) [EC 2. 7. 4. 9] being also retarded by the same treat-ment.
2. The injections of adrenalin (15-25μg. hourly) was also found to be effective in inhibiting the DNA synthesis and thymidine kinase induction occuring in regenerating livers, although no such effects were produced in the case of hepatoma cells.
3. The effect of adrenalin was found to be the greatest when admi-nistered during an early period of regeneration, during which time the induction mechanism would still be operating, this effect becoming smaller when it was given later than 24 hours after partial hepatectomy.
4. Suggestions were put forward that the action of adrenalin might be more direct than that of cortisone and that it might be acting some-where at a stage preceding the S phase, probably at “dicho-phase” of mitosis cycle. The possible mode of action of cortisone was also discussed in relation to the behavior of lymphocytes.

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