Metabolism, protein

The strong hydrochloric acid, naturally present in the stomach, hydrolyses (adding on the elements of water) the foods containing proteins to form small amino acids for transport by the blood into cells. These small amino acid units are the starter building blocks for specific sequences of amino acids needed inside the cells for protein building. The proteins manufactured in the cells are different from those taken in as food, which is why they first have to be broken down into small units for eventual remaking and rearranging into those specifically required by the cells. 

There are approximately 20 separate amino acids that form various proteins of immense chain length, some with as many as 2000 units of different combinations in their chains. Each protein has its own characteristic shape some are long chains, some are spirals and some are more ball-like. Their shape often determines the specific and characteristic properties of the particular protein. 

Each protein operates best at a specific pH and temperature If these alter too much it loses its molecular shape and some of the peptide bonds break up. It is then said to be denatured . You will know that an egg white protein is transparent and runny, but when heated in a frying pan it hardens and becomes more rubbery. The egg s proteins have been denatured . 

During digestion, the proteins present in food are too large to pass directly through cell walls and membranes so they are broken down into the more simple amino acid units (by enzyme hydrolysis). These small amino acids are absorbed by the villi of 

The synthetic process is stimulated by a growth hormones and also by insulin. Many different proteins have different jobs. Some act as enzyme catalysts for other chemical reactions in the fluids and cells of the body. Some go to make haemoglobin, which is synthesized in the bone marrow others go to make material for muscles, hormones, collagen, elastin, etc. 

A substantial literature bears witness to the importance of investigating the effects of h amic substances on enzyme changes in plant tissues. In such studies it is usual to distinguish between an effect on enzyme development (synthesis), and an effect on enzyme activity yev se which is measured by adding the humic substances to the enzyme assay media. In this section, only protein synthesis generally and enzyme synthesis in particular, are considered because they relate directly to translation and/or transcription involving m-RNA. 

Bukvova and Tichy reported that HA influenced the development of phosphorylase in wheat plants during growth in sand culture, the nature of the effect depending on the concentration of the humic substances. At a concentration of lOmgl HA enhanced the development of phosphorylase 

Humic substances have been shown to influence the development of 

In all cases where humic substances influence the development of an 

There is only a meagre amount of relevant data available to substantiate 

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The adrenal cortex produces steroidal hormones that are associated with carbohydrate, fat, and protein metabolism, electrolyte balance, and gonadal functions (58). One of these, cortisone [53-06-5] ( ) demonstrated a remarkable ability to relieve the symptoms of inflammatory conditions... 

M. Dungelhoef, M. Rodehutscord, H. Spiekers and E. Pfeffer, Anim. Feed Sci. Technol., 1994,49, 1. M. I. Ferraz de Oliveira and T. Acamovic, in Proceedings of VII Symposium on Protein Metabolism and Nutrition, Evora, Portugal 1995, 1996 in press. 

FIGURE 23.25 The effects of cortisol on carbohydrate and protein metabolism in the liver. 

Chibnall, A. C., Protein Metabolism in the Plant, New Haven, Conn., Yale University... 

The glucocorticoids influence or regulate functions such as the immune response system, the regulation of glucose, fat and protein metabolism, and control of the anti-inflammatory response. Table 50-1 describes the activity of the glucocorticoids within the body. 

Regulation of blood pressure Metabolism of carbohydrates and protein Metabolism of fat... 

Elovaara E, Tossavainen A, Savolainen H. 1978. Effects of subclinical hydrogen sulfide intoxication on mouse brain protein metabolism. Exp Neurol 62 93-98. 

As the one of the main end products of protein metabolism in living organisms, urea is a primary source of organic nitrogen in soil (from animal urine, fertilizers, etc.). Monitoring the level of urea is important for medicine, as well as for environmental protection. Urease is an enzyme that breaks the carbon-nitrogen bond of amides to form carbon dioxide, ammonia and water. This enzyme is widely used for determination of urea in... 

Jones EA, Craigie A, Tavill AS, Franglen G, RosenoerVM Protein metabolism in the intestinal stagnant loop syndrome. Gut 1968 9 466-469. 

Phosphorylation Glycogen Metabolic Movements of Glycogen Fat Metabolic Movements of Fat Protein Metabolic Movements of Protein Tissue Cooperation Liver Muscle Ketone Bodies... 

Urea has been of interest to the biological oceanographer because of its role as an excretion product of protein metabolism, its function in osmoregulation, and its reported use as a nitrogen source for phytoplankton growth. 

Sreedevi, P., B. Sivaramakrishna, A. Suresh, and K. Radhakrishnaiah. 1992a. Effect of nickel on some aspects of protein metabolism in the gill and kidney of the freshwater fish, Cyprinus carpio L. Environ. Pollut. 77 59-63. 

Shukla, J.P. and K. Pandey. 1986a. Zinc induced changes in the nucleic acids and protein metabolism in the fingerlings of a freshwater murrel, Channa punctatus. Acta Hydrochim. Hydrobiol. 14 195-197. 

Fed diet containing 96 mg CN/kg ration, as cassava peel, for 72 days No effect on food consumption or protein metabolism 40... 

Reddy, P.M. and M. Bashamohideen. 1988. Toxic impact of fenvalerate on the protein metabolism in the branchial tissue of a fish, Cyprinus carpio. Current Sci. 57 211-212. 

Hydrocephaly decreases in weight of brain, lung, liver, and kidney decreases in liver glycogen, kidney proteins and alkaline phosphatase and disrupted brain DNA and protein metabolism (Kav-lock et al. 1982)... 

Diabetes mellitus (DM) is a group of metabolic disorders characterized by hyperglycemia and abnormalities in carbohydrate, fat, and protein metabolism. It results from defects in insulin secretion, insulin sensitivity, or both. Chronic microvascular, macrovascular, and neuropathic complications may ensue. 

Blockers have been used widely to ameliorate thyrotoxic symptoms such as palpitations, anxiety, tremor, and heat intolerance. They have no effect on peripheral thyrotoxicosis and protein metabolism and do not reduce TSAb or prevent thyroid storm. Propranolol and nadolol partially block the conversion of T4 to T3, but this contribution to the overall therapeutic effect is small. 

No single toxin is responsible for all of the signs and symptoms of uremia observed in stage 4 or 5 CKD. Toxins accumulate as a result of increased secretion, decreased clearance secondary to reduced metabolism within the kidney, and/or decreased renal clearance of by-products of protein metabolism. 

Vitamin Ba (pyridoxine, pyridoxal, pyridoxamine) like nicotinic acid is a pyridine derivative. Its phosphorylated form is the coenzyme in enzymes that decarboxylate amino acids, e.g., tyrosine, arginine, glycine, glutamic acid, and dihydroxyphenylalanine. Vitamin B participates as coenzyme in various transaminations. It also functions in the conversion of tryptophan to nicotinic acid and amide. It is generally concerned with protein metabolism, e.g., the vitamin B8 requirement is increased in rats during increased protein intake. Vitamin B6 is also involved in the formation of unsaturated fatty acids. 

Protein isolation, by conjugating, 13 748 Protein kinases, 20 832 Protein metabolism, anabolic steroids and, 13 5-6... 

Theory Cortisol (or hydrocortisone) was introduced in the year 1951, for the treatment of rheumatoid arthritis. It has a significant effect on protein metabolism. It also exerts widespread effects on carbohydrates, lipid and protein synthesis (or anabolism). The cardinal side effects such as excessive potassium excretion and sodium retention, enhanced gastric acidity, oedema, psychosis and negative nitogen balance are some of the exaggerated manifestations of the normal metabolite functions of cortisol. 

Cheung, C.W., Cohen, N.G., Raijman, L. (1989). Channeling of urea cycle intermediates in situ in permeabilized hepatocytes. J. Biol. Chem. 264,4038-4044. Cohen, P.P. (1954). Nitrogen metabolism of amino acids. In Chemical Pathways in Metabolism (Greenberg, D.M., Ed.), Vol. 2, pp. 1-46. Academic Press, New York. Fisher, R.B. (1954). Protein Metabolism. Methuen, London. 

Human exposure to low levels of phenol is widespread because it is contained in many consumer products including mouthwashes, gargles, tooth drops, throat lozenges, and ointments (Douglas 1972 EPA 1980). Phenol is a normal product of protein metabolism, and it is also a metabolite of benzene. In persons not exposed to phenol or benzene, the total phenol concentration in the urine generally does not exceed 20 mg/L and is usually <10 mg/L (ACGIH 1991). 

Biological monitoring for exposure to phenol is possible by measuring blood or urine levels of the parent compound. However, it should be noted that phenol and metabolites of phenol may also come from other sources. For example, phenol is a metabolite of benzene and of protein metabolism. Urine samples taken from male workers employed in the distillation of high-temperature phenolic fractions of tar revealed a phenol excretion rate of 4.20 mg/hour compared to a control rate of 0.53 mg/hour for non-exposed workers (Bieniek 1994). Samples were taken 4 hours into the workers workday, but the worker exposure levels were not reported. 

Some foods containing phenol have been identified (see Section 5.4.4) and could result in low levels of phenol exposure in children. In addition, phenol is produced endogenously as a breakdown product of protein metabolism normal concentrations in urine generally do not exceed 20 mg/L (ACGIH 1991). 

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