Insulin biological activity

REACTIVITY OP -S-S- BONDS IN RELATION ITITH INSULIN BIOLOGICAL ACTIVITY AND CATABOLISM... 

Serum ILA. All of the Insulln-llke activity (ILA) of serum cannot be neutralized by Insulin antibodies. 7 This has stimulated a great deal of research on the nature of servan factors which exhibit ILA in bloassays but are not Immunoreactlve and, hence, are not insulin. 3 one group has designated the forms of serum ILA as "free Insulin (Immimoreactive and biologically active in muscle and adipose tissue vitro) and "bound" Insulin (biologically active in adipose tissue vitro but not Immtmoreactive)... 

Human growth hormone is a very complex molecule biologically. Several diverse biological activities such as anaboHc, insulin-like, diabetogenic, and lactogenic activities have been ascribed to hGH, which also appears to promote water and salt retention. An in-depth discussion of these activities may be found in several excellent reviews available in the Hterature (34—36). 

It appears that chromium(III) is an essential trace element in mammalian metabolism and, together with insulin, is responsible for the clearance of glucose from the blood-stream. Tungsten too has been found to have a role in some enzymes converting CO2 into formic acid but, from the point of view of biological activity, the focus of interest in this group is unquestionably on molybdenum. 

Studies have shown that plants can make biologically active recombinant proteins through both transgenic and transient expression approaches. Although the plant post-translational machinery is similar to that of mammalian cells, there are some notable differences, e.g. differences in glycosylation, particularly the absence of sia-lation, which may impact the activity of certain proteins. The absence of mammalian enzymes may prevent complex maturation processes that are critical for the biological activity of proteins such as insulin. Fortunately these shortcomings affect the activity of only a limited number of proteins. 

M. Hashimoto, K. Takada, Y. Kiso, S. Muranishi, Synthesis of Palmitoyl Derivatives of Insulin and Their Biological Activities , Pharm. Res. 1989, 6, 171 - 176. 

Hormones are intercellular messengers. They are typically (1) steroids (e.g., estrogens, androgens, and mineral corticoids, which control the level of water and salts excreted by the kidney), (2) polypeptides (e.g., insulin and endorphins), and (3) amino acid derivatives (e.g., epinephrine, or adrenaline, and norepinephrine, or noradrenaline). Hormones maintain homeostasis—the balance of biological activities in the body for example, insulin controls the blood glucose level, epinephrine and norepinephrine mediate the response to the external environment, and growth hormone promotes normal healthy growth and development. 

The difficulty with HLB as an index of physicochemical properties is that it is not a unique value, as the data of Zaslavsky et al. (1) on the haemolytic activity of three alkyl mercaptan polyoxyethylene derivatives clearly show in Table 1. Nevertheless data on promotion of the absorption of drugs by series of nonionic surfactants, when plotted as a function of HLB do show patterns of behaviour which can assist in pin-pointing the necessary lipophilicity required for optimal biological activity. It is evident however, that structural specificity plays a part in interactions of nonionic surfactants with biomembranes as shown in Table 1. It is reasonable to assume that membranes with different lipophilicities will"require" surfactants of different HLB to achieve penetration and fluidization one of the difficulties in discerning this optimal value of HLB resides in the problems of analysis of data in the literature. For example, Hirai et al. (8 ) examined the effect of a large series of alkyl polyoxyethylene ethers (C4,C0, Cj2 and C 2 series) on the absorption of insulin through the nasal mucosa of rats. Some results are shown in Table II. 

The 3-indolylbenzoquinone fragment is a core structure in a number of biologically active natural products such as asterriquinones [49, 50]. The asterriquinones and demethylasterriquinones exhibit a wide spectrum of biological activities, including antitumor properties, and are inhibitors of HIV reverse transcriptase [51-53]. Asterriquinone Al has been shown to stop the cell cycle in G1 and promote apoptotic cell death [54, 55]. Recently, asterriquinone has been reported to be an orally active non-peptidyl mimetic of insulin with antidiabetic activity [56]. The simplest and the most straightforward approach for the synthesis of indol-... 

Insulin is a relatively simple protein consisting of 51 amino acids arranged as two polypeptide chains, an a-chain and (3-chain, connected by disulfide bonds the latter are necessary to maintain tertiary structure and biological activity (Fig 67.1). Although the amino acid... 

---