Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

E. coli fMet-tRNAfMEet and E. coli RNA plymerase (RNA nucleotidyltransferase; EC 2.7.7.6; nucleoside-triphosphate:RNA nucleotidyltransferase) form a 1:1 complex with an apparent association constant of 9.0 X 10(6)M-1 at 37 degrees. The affinity of polymerase to tRNA depends on the tRNA as well as the formyl methionine moiety. Core polymerase has a greatly reduced affinity for initiator tRNA. Optimal binding conditions are similar to those that are also optimal for binding initiator tRNA to ribosomes. Binding of initiator tRNA to polymerase stimulates the transcription of lambda plac DNA, as determined in a crude cell-free system for beta-galactosidase (EC 3.2.1.23; beta-D-galactoside galactohydrolase) synthesis as well as in a highly purified transcription system.
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PMID:Specific binding of formylated initiator-tRNA to Escherichia coli RNA polymerase. 78 83

The nucleotide sequence of part of the tra region of R100 including traJ and traY was determined, and the products of several tra genes were identified. The nucleotide sequence of traJ, encoding a protein of 223 amino acids, showed poor homology with the corresponding segments of other plasmids related to R100, but the deduced amino acid sequences showed low but significant homology. The first four amino acids at the N-terminal region of the TraJ protein were not essential for positive regulation of expression of traY, the first gene of the traYZ operon. The nucleotide sequence of traY shows that this gene may use TTG as the initiation codon and that it encodes a protein of 75 amino acids. Analysis of the traY gene product, which was obtained as the fusion protein with beta-galactosidase, showed that the N-terminal region of the product has an amino acid sequence identical to that deduced from the assigned frame but lacks formylmethionine. traY of plasmid F, which encodes a larger protein than the TraY protein of R100, is thought to use ATG as an initiation codon. However, a TTG initiation codon was found in the preceding region of the previously assigned traY coding frame of F. Interestingly, when translation of traY of F was initiated from TTG, the amino acid sequence homologous to the TraY protein of R100 appeared in tandem in the TraY protein of F. This may suggest that traY of F has undergone duplication of a gene like the traY gene of R100.
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PMID:Identification and characterization of the products from the traJ and traY genes of plasmid R100. 283 69

The gene infB codes for the two forms of translational initiation factor IF2: IF2 alpha (97 300 daltons) and IF2 beta (79 700 daltons). To determine whether the two forms differ at their N terminus, purified IF2 alpha and IF2 beta were subjected to 11 or more steps of Edman degradation. The N-terminal amino acid sequences are completely different, but match perfectly the DNA sequences at the beginning of the infB open reading frame and an in-phase region 471 bp downstream. A fusion was constructed between the proximal half of the infB gene and the lacZ gene lacking the region coding for the first eight amino acids. The fused gene expresses two products of 170 000 and 150 000 daltons, corresponding to the fused proteins IF2 alpha-beta-galactosidase and IF2 beta-beta-galactosidase, which confirms in vivo that the IF2 forms differ at their N terminus. A deletion of the 5'-non-translated region of the fused gene, including the Shine/Dalgarno ribosomal binding site, results in the expression of IF2 beta-beta-galactosidase but not IF2 alpha-beta-galactosidase. This strongly suggests that IF2 beta results from independent translation rather than from a precise proteolytic cleavage of IF2 alpha. Further evidence for initiation of protein synthesis at the putative IF2 alpha and IF2 beta start sites was sought by using an in vitro dipeptide synthesis assay. A DNA fragment containing the entire infB gene was cloned into three plasmid vectors and the resulting recombinant DNAs were used as templates in assays containing fMet-tRNA and various labelled aminoacyl-tRNAs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Two translational initiation sites in the infB gene are used to express initiation factor IF2 alpha and IF2 beta in Escherichia coli. 389 4

Aging is assumed to decrease lysosomal enzyme release from polymorphonuclear leukocytes (PMN). A synthetic chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) was utilized to stimulate enzyme release of PMN from 45 human subjects, 21 males and 24 females, ranging in age from 22-83 yr old. Results of the studies showed no sex differences in the stimulation of enzyme release for either age group. However, stimulation was found to significantly decline in both males and females over 50 yr old compared to subjects under 50 yr old. The linear formulae for beta-glucuronidase, beta-galactosidase and lysozyme in male subjects were Y = 6.5X + 617.2, Y = -1.9X + 311.5 and Y = -1.9X + 327.3 with correlation coefficient of -0.685, -0.352 and -0.401, respectively. The linear formulae in females were Y = -5.2X + 536.6, Y = -3.0X + 340.6 and Y = -1.7X + 333.6 with correlation coefficient of -0.582, -0.303 and -0.462, respectively. These findings suggest that there was an age-related decline of response to the stimulant, fMet-Leu-Phe.
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PMID:Age-related decline in lysosomal enzyme release from polymorphonuclear leukocytes after N-formyl-methionyl-leucyl-phenylalanine stimulation. 642 Jan 76