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C B Bruni

Publications and source records attributed to C B Bruni.

117 records · Page 7Linked to original sources
PubMed1968

Further purification and characterization of the acid alpha-glucosidase.

1. Centrifugation of rat liver acid glucosidase, which had been purified by adsorption on dextran gel, on a density gradient of sucrose showed the enzyme to be impure. 2. Preliminary purification of the enzyme before the gel filtration improved the final degree of purity of this preparation. Disc gel electrophoresis of this preparation showed a single band of protein. 3. The sedimentation co-efficient and the molecular weight determined on a sucrose gradient were 4.9-5.1s and 76000-83000 respectively for the rat liver enzyme, and 5.6s and 97000 for the acid alpha-glucosidase purified by means of the same procedure from the human kidney. 4. The Michaelis constants of rat liver and human kidney enzyme were 4.7x10(-3)m and 13.6x10(-3)m respectively with maltose as substrate. 5. The enzyme from both tissues was inhibited by tris and by erythritol. The inhibition of the rat liver acid glucosidase by erythritol was competitive.

Animals↗
PubMed1967

Purification of an acid alpha-glucosidase by dextran-gel filtration.

1. The behaviour of rat liver alpha-glucosidases on dextran gel (Sephadex G-100) columns was studied. A ;retardation' of an acid alpha-glucosidase activity was observed. This activity was identified as lysosome alpha-(1-->4)-glucosidase. A single gel-filtration step resulted in a 700-fold purification of the enzyme. The same technique was also used to purify the acid alpha-glucosidase of human kidney. 2. The acid alpha-glucosidases of both tissues show very similar pH optima when tested with maltose or glycogen as substrate.

Animals↗
PubMed1966

Dextran-gel filtration of enzymes in the presence of their high-molecular-weight substrates.

1. Trypsin and ribonuclease were filtered through dextran gel (Sephadex G-100) columns in the absence and presence of their respective substrates. In the presence of their high-molecular-weight substrates the enzymes emerged earlier from the columns. This appeared to be due to the reversible formation of specific enzyme-substrate complexes. 2. The possibility of separation of an enzyme from other proteins with similar molecular weights was demonstrated with trypsin and cytochrome c in the presence of casein.

Caseins↗
PubMedDate not supplied

Cloning and characterization of a Neisseria gene homologous to hisJ and argT of Escherichia coli and Salmonella typhimurium.

We have isolated from a genomic library of the pathogenic Neisseriae gonorrhoeae T2 strain, a gene encoding a putative protein of 268 amino acids which exhibited significant similarity to the hisJ and argT gene products of Salmonella typhimurium and Escherichia coli, periplasmic proteins deputed to amino acid transport within the cell. The gene is transcribed as a monocistronic mRNA species of about 960 nucleotides flanked by regulatory elements for initiation and termination of transcription that are efficiently recognized in an E. coli host.

Amino Acids↗
PubMedDate not supplied

Isolation of a cDNA clone encoding rat insulin-like growth factor-II precursor.

Insulin-like growth factor-I (IGF-I) and IGF-II are mitogenic polypeptides of relative molecular mass (Mr) approximately 7,500 isolated from human plasma each containing four peptide domains in a single chain and identical at more than 60% of their amino acid loci. The B- and A-domains of the IGFs are approximately 40% identical to the B- and A-chains of human insulin. IGF-I and IGF-II have similar in vitro biological activities and receptor reactivity, but are immunologically distinct. IGF-I appears to mediate the effects of growth hormone on cartilage to promote skeletal growth whereas IGF-II may have a special role in fetal development and in the central nervous system. To investigate the in vivo role of IGF-II, we have studied IGF-II biosynthesis in the BRL-3A rat liver cell line. BRL-3A cells synthesize and secrete a 7,484 Mr protein 93% identical to human IGF-II and representing rat IGF-II (rIGF-II). Rat IGF-II is synthesized as a approximately 22,000 Mr prepro-rIGF-II (ref. 12) from 12 S poly(A)+mRNA. In addition, approximately 20,000 Mr pro-rIGF-II has been identified in lysates of biosynthetically labelled intact BRL-3A cells. We report here the isolation of an almost complete cDNA clone for rIGF-II. Our results indicate that pro-rIGF-II is synthesized as a 156 amino acid peptide precursor (17,619 Mr) containing mature rIGF-II 1-67 at its amino-terminus and an 89-residue carboxy-terminal peptide extension.

Amino Acid Sequence↗