Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Chloroplasts inhibited by incubation with hydroxylamine in the light exhibit a low fluorescence yield upon illumination in the presence of dithionite sufficient to completely reduce the primary acceptor, Q. In the absence of magnesium ions, the fluorescence yield is the same as in control chloroplasts, suggesting that the reason for the low yield is a defect in the mechanism by which Mg2+ enhances the fluorescence. These chloroplasts were previouly shown to contain only low potential (Em7.8 = +80 mV) cytochrome b-559 (Horton, P. and Croze, E (1977) Biochim. Biophys. Acta 462, 86-101). 2. In Photosystem II particles, in heat-treated chloroplasts and in trypsin-digested chloroplasts, high potential cytochrome b-559 is absent and the variable fluorescence yield is again low. 3. Peas grown under intermittent light contain only one-fifth of the content of high potential cytochrome b-559 seen in fully greened plants, yet show high rates of water to methyl viologen electron transport. Aquisition of the high potential cytochrome b-559 accompanies synthesis of chlorophyll b, the onset of Mg-stimulated fluorescence and an increased variable yield of fluorescence. A similar correlation was seen during greening of dark-grown barley. 4. It is proposed that the high potential state of cytochrome b-559 is due to the same membrane properties which allow cation enhanced variable fluorescence, so that the presence of low potential cytochrome b-559 is accompanied by a decrease in variable fluorescence yield.
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PMID:Interactions between photosystem II components in chloroplast membranes. A correlation between the existence of a low potential species of cytochrome b-559 and low chlorophyll fluorescence in inhibited and developing chloroplasts. 68 9

The biological activity of synthetic polypeptides containing the amino acids of natural pure trypsin-bradykinin and snake-venom-bradykinin has been investigated. A series of tests for bradykinin-like activity in stimulating plain muscle, depressing the blood pressure and increasing capillary permeability was used on various species. A nonapeptide with the following structure: H-L-Arg-L-Pro-L-Pro-Gly-L-Phe-L-Ser-L-Pro-L-Phe-L-Arg-OH elicited qualitatively and quantitatively the effects of the pure natural bradykinins. An octapeptide with the following structure: H-L-Arg-L-Pro-Gly-L-Phe-L-Ser-L-Pro-L-Phe-L-Arg-OH also exerted bradykinin-like effects but was 50 to 100 times less active than the nonapeptide. Three other octapeptides and a heptapeptide were without any significant effect. Further work will demonstrate if the nonapeptide A is synthetic bradykinin or a peptide with bradykinin-like activity.NOTE ADDED SINCE SUBMISSION OF THIS PAPER: The data from this investigation were personally precommunicated to Elliott, Lewis, and Horton, who have since found that the structure of pure trypsin-bradykinin is identical with the structure of the nonapeptide A. Therefore, this synthetic nonapeptide is in fact synthetic bradykinin.
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PMID:Biological activity of synthetic polypeptides with bradykinin-like properties. 1375 32