TG2 (transglutaminase 2) is a calcium-dependent protein cross-linking enzyme which is involved in a variety of cellular processes. The threshold level of calcium needed for endogenous and recombinant TG2 activity has been controversial, the former being more sensitive to calcium than the latter. In the present study we address this question by identifying a single amino acid change from conserv...

Ureido-functionalized compounds play an indispensable role in important biochemical processes, as well chemical synthesis and production. Isocyanates, KOCN particular, are the preferred reagents for ureido functionalization of amine-bearing compounds. In this study, we evaluate potential urea a reagent to graft groups onto amines at relatively low temperatures (<100 °C) aqueous media. Urea i...

The serotonin transporter (SERT) on the plasma membrane is the major mechanism for the clearance of plasma serotonin (5-hydroxytryptamine (5HT)). The uptake rates of cells depend on the density of SERT molecules on the plasma membrane. Interestingly, the number of SERT molecules on the platelet surface is down-regulated when plasma 5HT ([5HT](ex)) is elevated. It is well reported that stimulati...

The final step in glycosylphosphatidylinositol (GPI) anchoring of cell surface proteins consists of a transamidation reaction in which preassembled GPI donors are substituted for C-terminal signal sequences in nascent polypeptides. In previous studies we described a human K562 cell mutant, termed class K, that accumulates fully assembled GPI units but is unable to transfer them to N-terminally ...

Thrazarine, O-[(3R)-2-diazo-3-hydroxybutyryl)]-L-serine, is a new antitumor antibiotic produced by Streptomyces coerulescens MH802-fF5. Thrazarine was isolated from culture filtrate by Sephadex LH-20 column chromatography and reversed phase HPLC. Thrazarine induced cytolysis of tumor cell lines co-cultured with nonactivated macrophages. This effect was tumor specific because the nontumorigenic ...

B(OCH2CF3)3, prepared from readily available B2O3 and 2,2,2-trifluoroethanol, is as an effective reagent for the direct amidation of a variety of carboxylic acids with a broad range of amines. In most cases, the amide products can be purified by a simple filtration procedure using commercially available resins, with no need for aqueous workup or chromatography. The amidation of N-protected amin...