Biomedical subjects

Ke Li

Publications and source records attributed to Ke Li.

At least 91 records · Page 5Linked to original sources

PubMed2003

Food groups and risk of esophageal cancer in Chaoshan region of China: a high-risk area of esophageal cancer.

The current study was designed to investigate the role of common foods in the etiology of esophageal cancer in the Chaoshan region of China. A large case-control study was conducted to investigate 1248 patients with squamous cell carcinoma of the esophagus and 1248 controls matched by sex, age, and hospitals. After adjusting for the effects of sex, age, occupation, areas of residence, income, alcohol intake, and cigarette usage, a strong association with a clear dose-response relationship was observed between the fermented fish sauce eaten weekly and esophageal cancer (P for trend less than 0.001). The results for pickles were similar to those for fermented fish sauce. A protective effect of fruits on esophageal cancer was observed, and this risk decreased (P for trend less than 0.001) as frequencies of fresh fruit intake increased. The risks from sowbelly and kipper were significantly higher in consumers than in nonconsumer, but the dose-response relationship was not statistically significant. No significant effects, however, were detected from vegetables, smoked foods, and so on. To the authors' knowledge, this is the first report on the relationship between fish juice and high risk of esophageal cancer in a population. Further epidemiological and experimental study are required to find a biological causal relationship between them.

Alcohol Drinking↗

PubMed2003

Conformational properties of nucleotide-based template-competitive HIV-1 reverse transcriptase inhibitors: analysis of enzyme binding modes.

Nucleotides 2-(4-azidophenacyl)thio-1,N6-etheno-2'-deoxyadenosine 5'-triphosphate 1 and its tetrafluoro analog 2 inhibit HIV-1 reverse transcriptase (RT) competitively relative to template. These template-competitive RT inhibitors (TCRTIs) were analyzed for conformational properties by molecular modeling and NMR analysis. Both inhibitors prefer sugar conformations of C2'-endo/C3'-exo with a high-anti glycosidic bond rotation and +sc/ap phosphate conformation (gamma). The major effect of the etheno group is to favor an extended, fully staggered anti conformation in the N1-C2-S-CH2 psi1 side chain rotation, and NMR analysis detects a long range sugar H4' to side chain phenyl meta-H NOE, a result consistent with this compact structure as an important contributor to the solution structure. The binding model generated places the phenyl side chain in a lipophilic pocket in the template grip region of the RT polymerase domain with the Mg-triphosphate complexed to active site carboxylates. The structures of the TCRTIs are compared with that of the template-competitive DNA polymerase inhibitor 2-(4-azidophenacyl)thio-2'-deoxyadenosine 5'-triphosphate 3, and a theoretical model for selectivity is proposed.

Binding, Competitive↗

PubMed2003

Identification of the metabolites of 9-nitro-20(S)-camptothecin in rats.

9-Nitro-20(S)-camptothecin is a novel anticancer drug. In this study, metabolites of 9-nitro-20(S)-camptothecin in rats were identified. Rats were dosed with the drug, and the metabolites in the bile were isolated and collected by high-performance liquid chromatography using a gradient elution. By LC/MSn(n =1-3), the biliary metabolites in addition to the unchanged drug were identified as 9-amino-20(S)-camptothecin (M3), 9-acetamido-20(S)-camptothecin (M4), and the glucuronide of 9-hydroxy-20(S)-camptothecin (M1) with the aid of the reference substances and the enzymatic hydrolysis. The accurate mass data for metabolites M2 and M5 were determined by a quadrupole time-of-flight mass spectrometer. Metabolite M5 was suggested to be the glutathione conjugate of 10-hydroxy-20(S)-campto-thecin, and M2 may arise from the loss of glutamic acid from M5. Metabolites M1 and M3 were also found in the urine, and M4 in the feces. Fecal metabolite M7 was confirmed to be 9-hydroxy-20(S)-camptothecin (the aglycon of M1) by being compared with the reference standard. The mercapturic acid conjugate of 10-hydroxy-20(S)-camptothecin (M6) was detected in the urine and feces by LC/MSn

Animals↗

PubMed2003

Interaction between hepatitis C virus core protein and translin protein--a possible molecular mechanism for hepatocellular carcinoma and lymphoma caused by hepatitis C virus.

AIM: To investigate the interaction between hepatitis C virus core protein and translin protein and its role in the pathogenensis of hepatocellular carcinoma and lymphoma. METHODS: With the components of the yeast two hybrid system 3, "bait" plasmids of HCV core the gene was constructed. After proving that hepatitis C virus core protein could be firmly expressed in AH109 yeast strains, yeast two- hybrid screening was performed by mating AH109 with Y187 that transformed with liver cDNA library plasmids-pACT2 and then plated on quadruple dropout (QDO) medium and then assayed for alpha-gal activity. Sequencing analysis of the genes of library plasmids in yeast colonies that could grow on QDO with alpha-gal activity was performed. The interaction between HCV core protein and the protein we obtained from positive colony was further confirmed by repeating yeast two - hybrid analysis and coimmunoprecipitation in vitro. RESULTS: A gene from a positive colony was the gene of translin, a recombination hotspot binding protein. The interaction between HCV core protein and translin protein could be proved not only in yeast, but also in vitro. CONCLUSION: The core protein of HCV can interact with translin protein. This can partly explain the molecular mechanism for hepatocellular carcinoma and lymphoma caused by HCV.

Carcinoma, Hepatocellular↗

PubMed2003

[Screening of the genes of hepatitis B virus PreS2 interacting proteins].

OBJECTIVE: To screen and clone the genes of proteins in hepatocytes interacting with hepatitis B virus (HBV) PreS2 by yeast-two hybridization technique. METHODS: The HBV PreS2 gene was amplified by polymerase chain reaction (PCR) and HBV PreS2 bait plasmid was constructed by using yeast-two hybridization system 3, then transformed into yeast AH109, followed by mating with yeast Y187 containing liver cDNA library plasmid in 2 YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-Ade-His) and synthetic dropout nutrient medium (SD/-Trp-Leu-Ade-His) containing X-alpha-gal for selecting positive blue clones, then amplified by PCR, sequenced, and performed bioinformatics analysis. RESULTS: HBV PreS2 gene was cloned successfully and expressed in yeast AH109.Twenty-six positive colonies were selected, among them, twelve containing metallothionein 2A, one cytochrome C oxidase II, two cytochrome P450 subfamily IV4F, two cytochrome c oxidase subunit 4 isoform 1, three albumin (ALB), one Na(+)K(+) transporting ATPase beta-1 polypeptide, two prealbumin, one lectin galactoside-binding subunit, and Two new genes with unknown function. CONCLUSION: Genes of HBV PreS2 interacting proteins have been successfully cloned, which brings some new clues for studying the biological functions of HBV PreS2 and related proteins.

Cloning, Molecular↗

PubMed2003

Pharmacokinetics of 9-nitro-20(S)-camptothecin in rats.

AIM: To study the pharmacokinetics and the excretion of 9-nitro-20(S)-camptothecin (9-NC) in rats. METHODS: Each rat was given a single dose at random by iv or ig administration. Serial plasma and excreta samples were collected and the pharmacokinetic behavior of 9-NC in rats was characterized by specific liquid chromatographic assays. Individual 9-NC plasma-concentration data were analyzed by both noncompartmental and compartmental analysis. For dose proportionality, AUC- and Cmax-dose relationships were evaluated by linear regression, and t1/2 and CLtot were compared by an analysis of variance model. Also, the excretion of the parent drug was estimated. RESULTS: After iv administration of 9-NC at the doses of 1.5, 3, and 6 mg/kg, the t1/2 values for 9-NC were estimated to be 0.5, 0.5, and 0.7 h, respectively, and the mean AUC0-t values were 633, 1606, and 3011 h.microg.L(-1), respectively. 9-NC was rapidly absorbed, reaching mean Cmax of 203, 417, and 1150 microg/L at Tmax of 0.3, 0.2, and 0.3 h at the doses of 3, 6, and 12 mg/kg, respectively. The mean AUC0-t values were 269, 439, and 881 h.microg.L(-1), and the mean t1/2 values were 1.7, 0.9, and 0.9 h, respectively. The absolute oral bioavailability of 9-NC was calculated to be 14.6 %, which was consistent with the ratio of the total cumulative excretion in the urine and bile by ig to that by iv injection. CONCLUSION: The kinetic process of 9-NC in rats in vivo was best fitted to a two-compartmental model. For iv administration, the pharmacokinetics are not dose-dependent. The oral bioavailability of 9-NC was low. Renal excretion was the primary elimination route of the parent drug after iv administration, however, after ig administration the unchanged drug was largely excreted in the feces because of the poor absorption.

Administration, Oral↗

PubMed2003

[Determination of 9-nitrocamptothecin in rat plasma and tissues by high performance liquid chromatography].

AIM: To develop a sensitive, specific and accurate method for quantifying 9-nitrocamptothecin in rat plasma and tissues and to study the distribution of 9-nitrocamptothecin in rat tissues. METHODS: Plasma and tissue samples were prepared based on a simple liquid-liquid extraction and separation through a Hypersil BDS C18 column. The mobile phase for plasma samples and tissue samples consisted of a mixture of acetonitrile-water-formic acid (35:65:2) and a mixture of acetonitrile-water-formic acid (30:70:2), respectively. The UV detector was set at 370 nm. RESULTS: A linear calibration curve of 9-nitrocamptothecin in plasma was obtained in the concentration range of 25-1,600 micrograms.L-1, and the quantitation limit of plasma and tissues was 25 micrograms.L-1. A linear range of concentrations for 9-nitrocamptothecin in heart, lung, spleen, stomach, fat, womb, and ovary was 10-1,000 ng.g-1, and the quantitation limit was 10 ng.g-1. A linear range of concentrations for 9-nitrocamptothecin in brain, kidney, liver, intestine, smooth muscle, skeletal muscle, and tectical was 5-500 ng.g-1, and the quantitation limit was 5 ng.g-1. The intra- and inter-run precision was measured to be below 11%. The inter-run accuracy was less than 5% for the analyte. After i.v. administration of 9-nitrocamptothecin, the drug was distributed extensively in rat in vivo. The concentration in lung was the highest, and the drug was accumulated in lung and liver. Following ig administration, the concentration in stomach was higher than that in other organs. CONCLUSION: The method is shown to be accurate and convenient, and suitable for preclinical pharmacokinetic studies of 9-nitrocamptothecin.

Animals↗

PubMed2003

[Changes in the VASP expression feature of endothelial cells under steady laminar flow].

To investigate the effects of physiological shear stress on the vasodilator-stimulated phosphoprotein (VASP) location and expression changes associated with actin remodeling, we isolated and cultured human umbilical endothelial cells(HUVECs) with trypsin digestion. A parallel-plated flow chamber device was used to create laminar shear stress in vitro. The distributions of VASP and microfilaments in cells were observed by double staining with Alexa488 and rhodamine-phalloidin. Changes of VASP expression and phosphorylation were analyzed quantitatively with Western blot before and after exposure to shear flow for different times. We found that, under a shear stress of 10 dyn/cm2, HUVECs were elongated and oriented gradually to the flow direction. Microfilaments were recruited and oriented also to the flow direction with thicker VASP, specially targeted to their extremities. Western blotting data showed a rapid phosphorylation of VASP, and an increase of total VASP expression which peaked at 2 h (2 folds), then recovered until 8 h, followed by a slow increase again. These results suggest that VASP is a potential component which participates in the regulation of cell actin remodelling induced by shear flow.

Cell Adhesion Molecules↗

PubMed2003

[A telemedical consultation system based on multicast].

That the multicast technology is fit for telemedical consultation application has been developed on the basis of the features analysis of medical consultation action. A scheme of the telemedical consultation application based on the multicast technology has been designed. The features of this scheme are: unrestrained joining in and quitting, simultaneous control over the transport information of doctor and patient, extending, and simulating consultation scene. And the implementation of this scheme is discussed.

Computer Communication Networks↗

PubMed2003

[Synergetic transactivating effect of HCV core and HBV X proteins on SV40 early promoter/enhancer].

BACKGROUND: To investigate the synergetic transactivating effects of HCV core and HBV X proteins. METHODS: HCV core and HBV X protein-expressing plasmids were constructed with the vector pcDNA3.1(-). The plasmids were transfected into HepG2 cells and cotransfected Hep2 cells with reporter plasmid Psv-lacZ by lipofectamine plus reagents. The virus proteins produced in transient expression system were detected at the transcription and translation levels. The activity of b-galactosidase was detected, which reflected the transactivating function of the proteins. RESULTS: The expression of plasmids were detected in soluble protein cell extracts of transiently transfected HepG2 cells. HCV core protein activated the b-galactosidase expression at a value 4.9 times higher than the control, while HBV X protein activated at a value 3.5 times. It arrived at 9 times transfected with the plasmids simultaneously. The activating effect increased in relation to the amount of plasmids. CONCLUSIONS: The results suggested that the two kinds of virus proteins have transactivating effect on SV40 early promoter/enhancer, and they acted synergistically. These contribute to explain the mechanisms of liver injury or tumorigenesis induced by HCV or/and HBV infection.

Animals↗

PubMed2003

[Effect of p16 gene on carcinogenesis of hepatitis B virus related hepatocellular carcinoma].

OBJECTIVE: To investigate the relation between p16 gene expression and the carcinogenesis and progress of hepatitis B virus (HBV) related hepatocellular carcinoma (HCC). METHODS: In 35 specimens of HCC tissue and the adjacent liver tissue, the integration of HBV X gene was detected by polymerase chain reaction (PCR) and Southern blot. The point mutation of exon-1alpha, 2 and 3 of p16 gene were detected by PCR-single strand conformation polymorphism (SSCP). The expression of p16 mRNA and p16 protein was detected by RT-PCR and Western blot. RESULTS: The integration of X gene correlated with the expression loss of p16 mRNA and p16 protein in HCC (P < 0.05). The expression loss rates of p16 protein in HCC and adjacent tissues were 62.9% (22/35) and 40.0% (14/35) with significant difference (P < 0.05). The expression loss of p16 protein in HCC correlated with the differentiation degrees of HCC and the infiltration of tumor cells (P < 0.05). CONCLUSION: The integration of X gene correlates with the expression loss of p16 protein. The alteration of p16 gene, playing an important role in all stages of hepatocarcinogenesis, correlates with the progress and invasion of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗

PubMed2003

PG490-88, a derivative of triptolide, causes tumor regression and sensitizes tumors to chemotherapy.

Treatment of solid tumors with combinations of chemotherapeutic agents has not led to significant increases in long-term survival. Recent studies support a role for inhibitors of checkpoint arrest as a means to enhance the cytotoxicity of chemotherapy. We have shown previously that triptolide (PG490), an oxygenated diterpene derived from a Chinese medicinal plant, induces apoptosis in cultured tumor cells and sensitizes tumor cells to topoisomerase inhibitors by blocking p53-mediated induction of p21. Here we extend our studies to a tumor xenograft model and evaluate the efficacy and safety of PG490-88 (14-succinyl triptolide sodium salt), a water-soluble prodrug of PG490. We also look at the combination of PG490 or PG490-88 with CPT-11, a topoisomerase I inhibitor, in cultured cells and in the tumor xenograft model. We show that PG490-88 is a safe and potent antitumor agent when used alone, causing tumor regression of lung and colon tumor xenografts. We also show that PG490-88 acts in synergy with CPT-11 to cause tumor regression. A phase I trial of PG490-88 for solid tumors began recently and safety and optimal dosing data should accrue within the next 12 months. Our findings that PG490-88 causes tumor regression and that it acts in synergy with DNA-damaging chemotherapeutic agents suggest a role as an antineoplastic agent and chemosensitizer for the treatment of patients with solid tumors.

Animals↗

PubMed2003

Screening of augmenter of liver regeneration-binding proteins by yeast-two hybrid technique.

OBJECTIVE: To investigate the biological function of augmenter of liver regeneration (ALR), we used yeast-two hybrid technique to detect proteins in hepatocytes interacting with ALR. METHODS: ALR bait plasmid was constructed by using yeast-two hybrid system 3, then transformed into yeast AH109. The transformed yeast was mated with yeast Y187 containing liver cDNA library plasmid in a 2XYPDA medium. Diploid yeast was plated on a synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-alpha-gal for selection and screening. After extracting and sequencing of the plasmid from blue colonies. Analysis was performed by bioinformatics. RESULTS: Of 36 colonies sequenced, 14 are metallothionein, 12 albumin, and 3 selenoprotein P. One colony is a new gene with unknown function. CONCLUSION: The successful cloning of gene of ALR interacting protein has paved the way for studying the physiological function of ALR and associated proteins.

Animals↗

PubMed2002

DYRK3 activation, engagement of protein kinase A/cAMP response element-binding protein, and modulation of progenitor cell survival.

DYRKs are a new family of dual-specificity tyrosine-regulated kinases with emerging roles in cell growth and development. Recently, we discovered that DYRK3 is expressed primarily in erythroid progenitor cells and modulates late erythropoiesis. We now describe 1) roles for the DYRK3 YTY signature motif in kinase activation, 2) the coupling of DYRK3 to cAMP response element (CRE)-binding protein (CREB), and 3) effects of DYRK3 on hematopoietic progenitor cell survival. Regarding the DYRK3 kinase domain, intactness of Tyr(333) (but not Tyr(331)) within subdomain loop VII-VIII was critical for activation. Tyr(331) plus Tyr(333) acidification (Tyr mutated to Glu) was constitutively activating, but kinase activity was not affected substantially by unique N- or C-terminal domains. In transfected 293 and HeLa cells, DYRK3 was discovered to efficiently stimulate CRE-luciferase expression, to activate a CREB-Gal4 fusion protein, and to promote CREB phosphorylation at Ser(133). Interestingly, this CREB/CRE response was also supported (50% of wild-type activity) by a kinase-inactive DYRK3 mutant as well as a DYRK3 C-terminal region and was blocked by protein kinase A inhibitors, suggesting functional interactions between protein kinase A and DYRK3. Finally, DYRK3 expression in cytokine-dependent hematopoietic FDCW2 cells was observed to inhibit programmed cell death. Thus, primary new insight into DYRK3 kinase signaling routes, subdomain activities, and possible biofunctions is provided.

Amino Acid Motifs↗

PubMed2002

[Mutual interaction between hepatitis C virus core protein and translin, a recombination hotspot binding protein].

OBJECTIVE: To study the role of the core protein of hepatitis C virus (HCV) in HCV pathogenesis and investigate the molecular mechanism of this protein in tumorigenesis. METHODS: By using the yeast two hybrid system 3, the bait plasmids of the gene of the core protein of HCV was constructed and transfected into AH109 yeast strain. Then this transfected AH109 yeast was mated with Y187 yeast containing liver cDNA library plasmids and cultured on quadropledropout (QDO) medium covered with x-alpha-gal and assayed for alpha-gal activity. The blue colonies growing on QOD were collected to extract the plasmids to transform Escherichia coli. Plasmids were extracted from the bacterium and sequenced. After bioinformatic analysis translin, a recombination hotspot binding protein interacting with HCV core protein was found. To further prove the interaction between translin protein and HCV core protein translation was performed by using reticulocyte lysate and immunoprecipitation in vitro. RESULTS: Among the 30 positive colonies, a colony was translin. The interaction between HCV core protein and translin protein could be proved not only in yeast, but also in vitro. CONCLUSION: The core protein of HCV can interact with translin protein, this can explain partly the tumorigenesis of HCV.

Cell Transformation, Neoplastic↗

PubMed2002

Simultaneous determination of nicotinamide, pyridoxine hydrochloride, thiamine mononitrate and riboflavin in multivitamin with minerals tablets by reversed-phase ion-pair high performance liquid chromatography.

A reversed-phase ion-pair high performance liquid chromatographic method (HPLC) has been developed and validated for the routine analysis of nicotinamide, pyridoxine hydrochloride, thiamine mononitrate and riboflavin in multivitamin with minerals tablets. HPLC separation of the vitamins was performed on a Hypersil C(18) column and detected by ultraviolet absorbance at 280 nm. The use of methanol-aqueous 0.5% acetic acid solution (18:82, v/v; containing 2.5 mM sodium hexanesulfonate, pH = 2.8) as the mobile phase at a flow-rate of 1.2 mL/min enables the baseline separation of the four analytes free from interferences with isocratic elution at 30 degrees C. The analysis time was 17 min per injection. The method was linear in the ranges of 5-90, 2.5-90, 5-95 and 25-450 micro g/mL for thiamine mononitrate, riboflavin, pyridoxine hydrochloride and nicotinamide, respectively. The average coefficients of variation of within- and between-day assays were 2.2 and 3.6% for thiamine mononitrate, 1.8 and 2.4% for riboflavin, 1.3 and 1.7% for pyridoxine hydrochloride and 1.0 and 1.5% for nicotinamide, respectively. The average recoveries of thiamine mononitrate, riboflavin, pyridoxine hydrochloride and nicotinamide were 97.0, 97.2, 98.9 and 100.4% for the tablets, respectively. The method has been successfully applied to the simultaneous determination of nicotinamide, pyridoxine hydrochloride, thiamine mononitrate and riboflavin in multivitamin with minerals tablets.

Chromatography, High Pressure Liquid↗

PubMed2002

Template-competitive inhibitors of HIV-1 reverse transcriptase: design, synthesis and inhibitory activity.

We report the design, synthesis and activity studies on a novel class of template-competitive reverse transcriptase inhibitors (TCRTIs). The TCRTIs are 1,N(6)-etheno analogues of a series of dATP-based template-competitive DNA polymerase inhibitors synthesized in our laboratory (Moore, B. M.; Jalluri, R.; Doughty, M.B. Biochemistry 1996, 35, 11634). Thus, nucleotides 2-(4-azidophenacyl)thio-1,N(6)-etheno-2'-deoxyadenosine 5'-triphosphate 1, the tetrafluoro analogue 2-(4-azido-2,3,5,6-tetrafluorophenacyl)thio-1,N(6)-etheno-2'-deoxyadenosine 5'-triphosphate 2 and its analogues were synthesized by alkylation of 2-thio-1,N(6)-etheno-2'-deoxyadenosine 5'-monophosphate with the corresponding chloro- or bromo-alkyl halides and converted to the triphosphate. Kinetically, nucleotides 1 and 2 are both competitive inhibitors of reverse transcriptase versus template/primer with K(i)'s of 8.0 and 7.4 microM, respectively, and non-competitive inhibitors versus TTP with K(i)'s of 15 and 10 microM, respectively. Nucleotide 3, which differs from 1 only in that it lacks the etheno group, non-complementary nucleotide triphosphates, and related monophosphates and nucleosides, are completely inactive as inhibitors of reverse transcriptase at concentrations up to 1 mM. Photoinactivation of RT by 1 was both time- and concentration-dependent, and protected by template/primer but not by dNTPs. The concentration-dependent inactivation data gave a K(D,app) of 17.2 microM and maximum inactivation of 90%, and radiolabeled [beta, gamma-32P]-1 photoincorporated specifically and covalently into the p66 subunit of RT. Thus the photoinactivation data support our main conclusion from the kinetic data that this class of RT inhibitors are non-substrate and template-competitive.

Binding, Competitive↗

PubMed2002

Characterization of a binding site for template competitive inhibitors of HIV-1 reverse transcriptase using photolabeling derivatives.

Analogues of a novel class of template-competitive reverse transcriptase inhibitors (Li, K.; Lin, W.; Chong, K. H.; Moore, B. M.; Doughty, M. B. Bioorg. Med. Chem. 2002, 10, 507) were analyzed as photoprobes of HIV-1 reverse transcriptase (RT) heterodimer. The two photoprobes, 2-(4-azidophenacyl)thio-1,N(6)-etheno-2'-deoxyadenosine 5'-triphosphate 2 and the tetrafluoro analogue 2-(4-azido-2,3,5,6-tetrafluorophenacyl)thio-1,N(6)-etheno-2'-deoxyadenosine 5'-triphosphate 3, photodecomposed at 3500 A with half-lives of 4.0 and 2.5 min, respectively. Analysis of the photoproducts of 2m demonstrated that the etheno group is stable but the azido decomposes primarily to the 2-(S-[3H-diazepinon-4-yl]thio)-1,N(6)-etheno-dAMP. Photolysis of both 2 and 3 with RT resulted in a time-dependent loss of activity, with maximum inactivation of 83 and 60%, respectively. Both 2 and 3 showed concentration-dependent photoinactivation of RT in the concentration range from 0 to 100 microM, with EC(50)s of 20 and 25 microM and maximum inactivation of 80 and 60%, respectively. Both the time and concentration dependent photoinactivation were strongly protected by template-primer, but only poorly inhibited by even high concentrations of TTP. Radiolabeled analogues [beta,gamma-(32)P]-2 and [beta,gamma-(32)P]-3 photoincorporated into the p66 subunit, an incorporation also protected by template primer. Identification of the site of incorporation was problematic for both photoprobes, but evidence presented is consistent with labeling sites for the phenacyl side chains of both 2 and 3 in the template grip. Nevertheless, the photoinactivation and incorporation data are consistent with our earlier conclusions from the kinetic data that these inhibitors are specific for the free form of RT in competition with template/primer, and thus represent a novel class of inhibitors.

Adenosine Triphosphate↗