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131.
J N van Balgooy 《Experientia》1987,43(9):1034-1037
The plant amino acid canavanine and its hydrolytic product canaline were successfully separated and identified by Reverse Phase High Performance Liquid Chromatograph (RP-HPLC). This procedure was used to demonstrate the arginase-mediated cleavage of canavanine to yield canaline and urea, and the subsequent formation of a Schiff's base complex between canaline and pyridoxal phosphate. Both aforementioned reactions were demonstrated by RP-HPLC. 相似文献
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133.
Beta 2-microglobulin from serum associates with MHC class I antigens on the surface of cultured cells 总被引:3,自引:0,他引:3
Beta 2-microglobulin (beta 2-m) is a highly conserved polypeptide (12,000 molecular weight; 12K) noncovalently associated with the heavy chain (45-48K) of the major histocompatibility complex (MHC) class I antigens. Its synthesis is required for expression of the HLA-A/B and H-2K/D heavy chains at the cell surface; beta 2-m is also associated with the human cell-surface antigens T6 and M241 isolated from thymocytes. However, on the T leukaemic cell line MOLT-4 some of the T6 antigens contain a different 12K subunit, termed beta t (refs 3, 7, 8). Purified human beta 2-m can exchange partially both with human beta 2-m associated with HLA-antigens, and with mouse beta 2-m associated with murine alloantigens. As MOLT-4 cells were grown in the presence of fetal calf serum (FCS) and as serum is known to contain some free beta 2-m, we examined whether beta t was bovine beta 2-m which had replaced endogenous beta 2-m on the surface of the cell. Here we show both that beta 2-m from FCS or human serum (HuS) used in cell culture can exchange with beta 2-m on the cell surface, and that beta t is in fact bovine beta 2-m. 相似文献
134.
J. de Koning A. M. I. Tijssen J. A. M. J. van Dieten T. R. Koiter G. A. Schuiling G. P. van Rees 《Cellular and molecular life sciences : CMLS》1986,42(1):60-62
Summary The patterns of LH secretion during constant stimulation of the pituitary glands of estradiol-treated ovariectomized rats with a maximally stimulating amount of LH-RH in vivo and in vitro correspond with each other qualitatively and quantitatively. In vitro the changes with time of the LH secretion rate are somewhat retarded, especially the occurrence of desensitization. 相似文献
135.
Recognition sequence of bacteriophage phi X174 gene A protein--an initiator of DNA replication 总被引:8,自引:0,他引:8
A D van Mansfeld S A Langeveld P D Baas H S Jansz G A van der Marel G H Veeneman J H van Boom 《Nature》1980,288(5791):561-566
Gene A protein, the initiator protein of bacteriophage phi X174 DNA replication, cleaves synthetic single-stranded oligodeoxyribonucleotides at the same site as the corresponding sequence at the phi X origin. The results identify the recognition sequence within the decamer CAACTTGATA which is cleaved next to the G residue. Further requirements for cleavage of double-stranded DNA by the gene A protein are supercoiling and an A + T-rich domain adjacent to the recognition sequence. 相似文献
136.
Summary 2 yellow naphthoquinone derivatives were isolated from several pathogenic strains ofHendersonula toruloidea Nattrass. They were identified as 2,7-dimethoxy-6-ethyl-5-hydroxy-1,4-naphthoquinone and 2,7-dimethoxy-5-hydroxy-6-(1-acetoxyethyl)-1,4-naphthoquinone by means of physico-chemical methods.Thanks are due to Mr A.J.M. van Beijnen, Laboratory for Organic Chemistry, State University of Utrecht, for optical rotation measurements.The authors are indebted to Mr C. Versluys, Analytical Laboratory, State University of Utrecht, for measuring the mass spectra.We thank Mr J. W. Marsman, Institute for Organic Chemistry TNO, Utrecht, for the PMR-spectra. 相似文献
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140.
Sequence of cDNA encoding human insulin-like growth factor I precursor 总被引:10,自引:0,他引:10
M Jansen F M van Schaik A T Ricker B Bullock D E Woods K H Gabbay A L Nussbaum J S Sussenbach J L Van den Brande 《Nature》1983,306(5943):609-611
Somatomedins (SM) or insulin-like growth factors (IGF) constitute a heterogeneous group of peptides with important growth-promoting effects in vitro as well as in vivo. Amino acid sequences have been determined for only two of them, IGF-I and IGF-II, which are highly homologous. IGF-I, which is identical with SM-C, is composed of 70 amino acid residues and IGF-II contains 73 amino acids and may be identical with SM-A. Other peptides with different charge properties but with similar SM-like or insulin-like behaviour in biological and receptor assays, have been described but have not yet been fully characterized. The liver is known to be a major site of production of these peptides, but many other tissues--especially in the fetus--may synthesize them as well. We report here the nucleotide sequence of a human liver cDNA encoding the complete amino acid sequence of IGF-I. The IGF-I coding region is flanked by sequences encoding an amino-terminal peptide of at least 25 amino acid residues and a carboxyl-terminal peptide of 35 amino acids. This provides evidence that IGF-I is synthesized as a precursor protein and that formation of IGF-I from this precursor requires proteolytic processing at both ends. 相似文献