Peter K Chiang

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A cell motility-stimulating factor has been isolated, purified, and partially characterized from the serum-free conditioned medium of human A2058 melanoma cells. We term this activity "autocrine motility factor" (AMF). AMF has the properties of a protein with an estimated size of 55 kDa. At concentrations of 10 nM or less, AMF stimulated the random or(More)
S-Adenosylmethionine (AdoMet or SAM) plays a pivotal role as a methyl donor in a myriad of biological and biochemical events. Although it has been claimed that AdoMet itself has therapeutic benefits, it remains to be established whether it can be taken up intact by cells. S-Adenosylhomocysteine (AdoHcy), formed after donation of the methyl group of AdoMet(More)
Chemotherapy against human African trypanosomiasis relies on four drugs that cause frequent and occasionally severe side-effects. Because human African trypanosomiasis is a disease of poor people in Africa, the traditional market-driven pathways to drug development are not available. One potentially rapid and cost-effective approach to identifying and(More)
S-adenosylhomocysteine hydrolase (SAHH) is a key regulator of S-adenosylmethionine-dependent methylation reactions and an interesting pharmacologic target. We cloned the SAHH gene from Plasmodium falciparum (PfSAHH), with an amino acid sequence agreeing with that of the PlasmoDB genomic database. Even though the expressed recombinant enzyme, PfSAHH, could(More)
S-Adenosylhomocysteine (AdoHcy), formed after the donation of the methyl group of S-adenosylmethionine to a methyl acceptor, is hydrolyzed to adenosine and homocysteine by AdoHcy hydrolase physiologically. The administration of the inhibitors of AdoHcy hydrolase to cells or animals normally results in an accumulation of cellular AdoHcy higher than those(More)
3-Deazaneplanocin, a new carbocyclic analog of adenosine, was synthesized as an inhibitor of S-adenosylhomocysteine hydrolase. The Ki of 3-deazaneplanocin for a purified hamster liver preparation of S-adenosylhomocysteine hydrolase was 5 X 10(-11) M, making this inhibitor 250-fold more potent than the previously known most potent inhibitor of this enzyme,(More)
5'-Methylthioadenosine nucleosidase (EC 3.2.2.9), the enzyme which catalyzes hydrolytic cleavage of 5'-methylthioadenosine with the formation of adenine and 5'-methylthioribose, has been purified to homogeneity from Lupinus luteus seeds. The nucleosidase has a native molecular weight of 62 000 and consists of two identical subunits, as judged by gel(More)
When isolated apical membrane vesicles prepared from cultured A6 epithelia were incubated in vitro with the methyl donor S-adenosylmethionine, the control rate of amiloride-inhibitable sodium transport was doubled. The methylation inhibitors 3-deazaadenosine and S-adenosyl homocysteine returned the S-adenosyl-methionine-stimulated sodium transport to(More)
To more fully characterize the behavioral excitatory effects observed with certain diphenyl-substituted antimuscarinics, various behavioral effects of benactyzine, a prototype excitatory antimuscarinic, was evaluated in rats. These effects were compared to those of cocaine, atropine, and azaprophen, a muscarinic antagonist that contains both the diphenyl(More)
Prejunctional muscarinic receptors from the deep muscular plexus of canine ileum were studied, and their properties were compared with those of the postjunctional receptors of the circular smooth muscle. In the purified synaptosomal fraction (a fraction containing primarily the axonal varicosities of deep muscular plexus), the muscarinic ligand(More)