Various derivatives of the peptide component of subtilisinmodified ribonuclease have been described (1). Changes were produced in one or more of the three primary amino groups on Residues 1 and 7 in the parent compound.1 A derivative, in which acetylation of all three amino groups had been effected, was the only one showing a significant change in ability to regenerate enaymic activity when mix...

The S-carboxymethyl derivative chains of crosslinked and noncrosslinked fibrins were prepared from purified human fibrinogen. For crosslinked fibrin, fibrinogen was clotted with thrombin in the presence of calcium and purified human factor XIII. For noncrosslinked fibrin, ethylenediaminetetraacetate was substituted for factor XIII and calcium. After reduction with dithiothrcitol and alkylation ...

We report a one-step method for the purification to homogeneity of a cysteine proteinase of Entamoeba histolytica (histolysin) by affinity chromatography of the soluble extract of the parasite on immobilized phenylalanyl(2-phenyl)aminoacetaldehyde semicarbazone. The enzyme has an apparent Mr of 26,000 by SDS/polyacrylamide-gel electrophoresis and 29,000 by gel chromatography. Its pH optimum var...

Lactate utilization was studied in an in situ perfused trout heart preparation that was capable of performing at levels similar to in vivo maximum cardiac performance. Hearts were perfused with modified Cortland saline containing O.Smmoll" iodoacetic acid (to block endogenous glycolysis) and varying amounts of lactate (1 or lOmmoir) . We confirmed previous observations that lactate utilization ...

Tubers of Solanum tuberosum L. var. Russet Burbank, Kennebec, and Targhee were stored at 95% relative humidity and at 1.7, 4.4, 5.8, 7.2 or 10 C. Rates of O(2) consumption were measured periodically by removing individual tubers from storage, excising discs of pith parenchyma tissue, and incubating the discs in a Gilson respirometer at 30 C. With all three varieties, data suggest a greater invo...

Methionine residues of the alpha and beta subunits of bovine lutropin (LH) and bovine thyrotropin (TSH) have been specifically alkylated with iodoacetic acid. The alpha subunit has been modified so that two of the four methionines are quantitatively alkylated (residues 8 and 33, in agreement with studies by Cheng, K.-W. (1976) Biochem. J. 159, 71-77). Reassociation of the modified alpha subunit...

Reduction and carboxymethylation of mouse submaxillary gland renin produced two polypeptide chains which were readily separated by gel filtration or sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weights of the two chains, termed heavy chain and light chain, were determined to be 30,000 and 5,458, respectively. Carboxymethylation of renin with radiolabeled iodoacetic a...

Iodine containing disinfection by-products (I-DBPs) and haloacetaldehydes (HALs) are emerging disinfection by-product (DBP) classes of concern. The former due to its increased potential toxicity and the latter because it was found to be the third most relevant DBP class in mass in a U.S. nationwide drinking water study. These DBP classes have been scarcely investigated, and this work was perfor...

The theory that /?-ecdysone initiates developmental changes during insect metamorphosis by causing an increase in intranuclear levels of potassium, together with a concomitant decrease in sodium levels, has been investigated by two methods. First, imaginal discs from late third instar larvae have been cultured with 0-2 /*g/ml of /?-ecdysone together with inhibitors of active ion transport. Non-...