Publisher Summary This chapter discusses the fundamental molecular properties of avidin and streptavidin. Carbohydrate-free avidin can be obtained by use of deglycosylating enzymes and it has been shown to be present in significant amounts in some commercial preparations from which it may be separated by use of lectin columns. Improvement on the original use of biotinyl cellulose came with the introduction of iminobiotinyl derivatives of Sepharose that utilized the pH dependence of the binding 24 to achieve efficient elution. In iminobiotin, the ureido group becomes a guanidinium group; the form in which this is uncharged is strongly bound. The gene for streptavidin has been cloned and sequenced with the ultimate objective of using it in general expression systems for detecting and isolating fusion proteins. The stability is greatly enhanced by biotin binding, because the total free energy of binding is about 330 kJ/mol of tetramer. The dissociation constant for biotin is so low that it can be estimated only from the ratio of the rate constants for binding and exchange. The binding is accompanied by a red shift of the tryptophan spectrum and by a decrease in fluorescence, either of which can be used as the basis for quantitative assays.

Avidin and streptavidin.

Nanomaterials offer new opportunities for cancer diagnosis and treatment. Multifunctional nanoparticles harboring various functions including targeting, imaging, therapy, and etc have been intensively studied aiming to overcome limitations associated with conventional cancer diagnosis and therapy. Of various nanoparticles, magnetic iron oxide nanoparticles with superparamagnetic property have shown potential as multifunctional nanoparticles for clinical translation because they have been used asmagnetic resonance imaging (MRI) constrast agents in clinic and their features could be easily tailored by including targeting moieties, fluorescence dyes, or therapeutic agents. This review summarizes targeting strategies for construction of multifunctional nanoparticles including magnetic nanoparticles-based theranostic systems, and the various surface engineering strategies of nanoparticles for in vivo applications.

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Targeting Strategies for Multifunctional Nanoparticles in Cancer Imaging and Therapy

Riboflavin (vitamin B-2) and health

The physiology and biochemistry of polyamines in plants

Publisher Summary This chapter describes the different aspects of vitellogenesis and oocyte assembly The major components of fish oocytes are derived from the blood-borne high-molecular-weight compound, vitellogenin, which is synthesized in the liver of oviparous vertebrates The classification of vitellogenin as a phospholipoglycoprotein indicates the crucial functional groups that are carried on the protein backbone of the molecule—namely, lipids, some carbohydrates, and phosphate groups In the rainbow trout, estrone administration leads to the induction of vitellogenin synthesis in the liver and its release into the bloodstream, but estrone displays only 5%–12% of the potency of estradiol The biochemical information concerning vitellogenin clearly indicates that a great deal of posttranslational modification must occur in the liver cell to reach the finished product seen in the serum An integral part of estradiol action is the observed hypercalcemia in vitellogenic fish, which can largely be ascribed to the calcium-binding properties of phosphorylated and highly charged, components of the native vitellogenin molecule

5 Vitellogenesis and Oocyte Assembly

Regulation of arginine decarboxylase and putrescine levels in Cucumis sativus cotyledons

Arginine decarboxylase which makes its appearance in Lathyrus sativus seedlings after 24 h of seed germination reaches its highest level around 5–7 days, the cotyledons containing about 60% of the total activity in the seedlings at day 5. The cytosol enzyme was purified 977-fold from whole seedlings by steps involving manganese chloride treatment, ammonium sulphate and acetone fractionations, positive adsorption on alumina C-γ gel, DEAE-Sephadex chromatography followed by preparative disc gel electrophoresis. The enzyme was shown to be homogeneous by electrophoretic and immunological criteria, had a molecular weight of 220000 and appears to be a hexamer with identical subunits. The optimal pH and temperature for the enzyme activity were 8.5 and 45 °C respectively. The enzyme follows typical Michaelis-Menten kinetics with a Km value of 1.73 mM for arginine. Though Mn2+ at lower concentrations stimulated the enzyme activity, there was no dependence of the enzyme on any metal for the activity. The arginine decarboxylase of L. sativus is a sulfhydryl enzyme. The data on co-factor requirement, inhibition by carbonyl reagents, reducing agents and pyridoxal phosphate inhibitors, and a partial reversal by pyridoxal phosphate of inhibition by pyridoxal · HCl suggests that pyridoxal 5'-phosphate is involved as a co-factor for the enzyme. The enzyme activity was inhibited competitively by various amines including the product agmatine. Highest inhibition was obtained with spermine and arcain. The substrate analogue, l-canavanine, homologue l-homoarginine and other basic amino acids like l-lysine and l-ornithine inhibited the enzyme activity competitively, homoarginine being the most effective in this respect.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1975.tb02465.x

Arginine Decarboxylase from Lathyrus sativus Seedlings

The crude extracts of 3-day-old etiolated seedlings of Lathyrus sativus contained two S-adenosyl-L-methionine decarboxylase activities. The artifactual putrescine-dependent activity was due to the H2O2 generated by diamine oxidase (EC 1.4.3.6) of this plant system and was inhibited by catalase. This observation was confirmed by using an electrophoretically and immunologically homogeneous preparation of L. sativus diamine oxidase. In the presence of putrescine, diamine oxidase, in addition to S-adenosylmethionine, decarboxylated L-lysine, L-arginine, L-ornithine, L-methionine and L-glutamic acid to varying degrees. The decarboxylation was not metal-ion dependent. The biosynthetic S-adenosylmethionine decarboxylase (EC 4.1.1.21) was detected after removing diamine oxidase specifically from the crude extracts by employing an immunoaffinity column. This Mg2+-dependent decarboxylase was not stimulated by putrescine or inhibited by catalase. The enzyme activity was inhibited by semicarbazide, 4-bromo-3-hydroxybenzoylamine dihydrogen phosphate and methylglyoxal-bis (guanylhydrazone). It was largely localized in the shoots of the etiolated seedlings and was purified 40-fold by employing a p-hydroxymercuribenzoate/AH-Sepharose affinity column, which also separated the decarboxylase activity from spermidine synthase.

/pdf/putrescine-sensitive-artifactual-and-insensitive-4mn999uqon.pdf

Putrescine-sensitive (artifactual) and insensitive (biosynthetic) S-adenosyl-L-methionine decarboxylase activities of Lathyrus sativus seedlings.

We have earlier shown that the estrogen-modulated riboflavin carrier protein (RCP) first isolated from the chicken egg is evolutionarily conserved in mammals and is elaborated by lactating mammary gland as demonstrated with rat mammary epithelial cells in culture and confirmed by isolation of the vitamin carrier from bovine milk. In view of several earlier reports that many milk proteins as well as other estrogen-inducible proteins are up-regulated and secreted into circulation in animal models and in women with neoplastic breast disease, we analyzed serum RCP levels in a double-blind study using a specific radioimmunoassay in pre- and post-menopausal women with clinically diagnosed breast cancer at early and advanced stages of the disease and compared these levels with those in normal age-matched control volunteers. Our data reveal that the serum RCP levels in cycling breast cancer patients are 3- to 4-fold higher (p < 0.01) than those in their normal counterparts. This difference in circulatory RCP levels between cancer patients and their age-matched normal counterparts is further magnified to 9- to 11-fold (p < 0.005) at the post-menopausal stage. In addition, there seems to be a good correlation between rising RCP levels and disease progression, since significantly higher RCP concentrations (p < 0.005) are encountered in patients with advanced metastasizing breast cancer versus those with early disease. Using specific monoclonal antibodies, RCP could be localized immunohistochemically in the cytoplasm of invading neoplastic cells of lobular and ductal carcinomas of the breast, indicating that the malignant cells are probably the source of the elevated serum RCP levels in breast cancer. These findings suggest that measurement of circulatory RCP and the immunohistochemical staining pattern of RCP in biopsy specimens could be exploited as an additional marker in diagnosis/prognosis of breast cancer in women.

P. Radhakantha Adiga

Papers

Regulation of arginine decarboxylase and putrescine levels in Cucumis sativus cotyledons

Arginine Decarboxylase from Lathyrus sativus Seedlings

Putrescine-sensitive (artifactual) and insensitive (biosynthetic) S-adenosyl-L-methionine decarboxylase activities of Lathyrus sativus seedlings.

Riboflavin Carrier Protein: A Serum and Tissue Marker for Breast Carcinoma

The interaction of riboflavin with a protein isolated from hen's egg white: A spectrofluorimetric study