Kg Of Protein Research Articles

An evaluation of protein requirements in methylmalonic acidaemia.

A 3-month-old girl and a 13-month-old boy with vitamin B12-unresponsive methylmalonic acidaemia were studied to determine responses to varying levels of protein intake of growth, nitrogen balance and organic acid metabolism. A linear increase in the excretion of methylmalonic acid was observed in both patients above a critical level of protein intake. The inflection point was judged to reflect a ceiling above which amino acid intake exceeded requirements and catabolism was initiated. Below this point in each infant there was a plateau of minimal excretion of methylmalonic acid. Within this plateau level a reasonable rate of growth and metabolic stability were achieved at intakes between 0.70 and 0.75 and between 0.75 and 1.17 g protein kg-1, respectively, indicating that there is a range of protein tolerance and the importance of an individual approach to the provision of protein in patients with methylmalonic acidaemia. In the 3-month-old infant, nitrogen equilibrium was achieved at protein intakes above 0.6 g kg-1 and modest nitrogen retention was attained at a protein intake of 0.75 g kg-1, a level at which the excretion of methylmalonic acid was minimal and weight gain satisfactory. A protein intake of 1.25 g kg-1 was required to achieve a level of nitrogen retention often considered optimal for normal growth; however, this infant demonstrated an elevated excretion of methylmalonic acid and was close to clinical illness at this level of protein intake. The 13-month-old infant demonstrated a normal level of nitrogen retention, minimal excretion of methylmalonic acid, and a satisfactory rate of growth at protein intakes of 1.0-1.17 g kg-1. The values should prove useful guidelines for the management of infants requiring minimal intakes of protein. In studies carried out at 18-20 months of age, supplementation of the basic diet containing 0.75 g kg protein-1 with a mixture of amino acids not containing the precursors of methylmalonic acid was associated with increase of retention of nitrogen and increased concentrations of some essential amino acids in plasma, but effects on growth and the excretion of methylmalonic acid were not significant.

Survival During Fasting-Reply

In Reply.— Dr Forbes' calculations on nonobese fasters are based on the scant published values, largely from 1906 to 1915 and including data of uncertain reliability. The value of 20 g of nitrogen per kilogram of weight lost derives from four such subjects (one aged 8 years), three of whom fasted only two weeks. Another lean subject who fasted five weeks showed a ratio of 10 g of nitrogen per kilogram, a value like those found in longer fasts by obese subjects. Studies of both obese and nonobese persons consistently show accelerated nitrogen mobilization early in fasting, including that of Dr Forbes, which gives a higher ratio of nitrogen per kilogram in the first two weeks. Even using the 20 g of nitrogen per kilogram value, estimated initial weight of 70 kg, and 23.5-kg loss during the hunger strikes, the resulting 470-g nitrogen loss (2.9 kg of protein) represents about

Enzymatic Synthesis of Sinapine from 1-O-Sinapoyl-β-ᴅ-glucose and Choline by a Cell-Free System from Developing Seeds of Red Radish (Raphanus sativus L. var. sativus)

A cell-free system from developing seeds of red radish (Raphanus sativus L. var. sativus) catalyzed the transfer of the sinapoyl moiety of 1-O-sinapoyl-β-ᴅ-glucose to choline to form O-sinapoylcholine (sinapine). A wide range of proportionality with respect to incubation time and protein concentration was found in the determination of this enzymatic activity using a high performance liquid chromatographic (HPLC) method. The transacylase activity showed an absolute acceptor specificity towards choline and a high hydroxycinnamoyl donor specificity with 1-sinapoylglucose. Maxim|al rate of sinapine formation was found to be around pH 7.0 in 0.08 M potassium phosphate buffer. The apparent Km values were 0.30 mм for 1-sinapoylglucose and 7.64 mм for choline. Change in extractable transacylase activities from different stages of seed development correlated well with the in vivo accumulation kinetics of sinapine. Maximal activity around 36 pkat seed-1 and 129μkat kg-1 protein was extracted from dark-green immature seeds, which are in the process of rapid sinapine accumulation. About 20% of this activity still has been found in dark-brown mature seeds. This enzymatic acitivity refers to an enzyme which can be classified as 1-sinapoylglucose: choline sinapoyltransferase (SCT).

Measurement of xanthine oxidase activity in some human tissues. An optimized method.

Xanthine oxidase activity in human liver or jejunum homogenates was measured by using 8-14C-hypoxanthine (HX) as a substrate. Products of oxidation were separated by thin-layer chromatography on MN Polygram cellulose and located by autoradiography. The percentage of oxidation was measured by liquid scintillation. Main parameters of the enzyme reaction have been optimized. Repeatability and reproducibility of the overall procedure give a variation coefficient of 6.3 and 7.7%, respectively. Minimal detectable enzymatic activity corresponds to an oxidation percentage of 1% (HX) for liver and jejunum. The reliability and practicability of this method allow a rapid diagnosis of xanthine oxidase deficiency. Normal values obtained by this optimized method range between 25 and 42 mukat . kg-1 protein for liver and 18 and 40 mukat . kg-1 protein for jejunum.

Ametryne and Prometryne as Sulfur Sources for Bacteria

Bacteria were isolated that could utilize quantitatively the s-triazine herbicide prometryne [N,N' -bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine] or ametryne [N-ethyl-N'-(1-methylethyl)-6-(methylthio)-1,3,5-triazine- 2,4-diamine], or both, as a sole source of sulfur for growth. The success of enrichments depended on previous exposure of the soil inoculum to s-triazine herbicides. Deaminoethylametryne [4-(1-methylethyl)amino-6-(methylthio)-1,3,5-triazine-2-(1H)-one], methylsulfonic acid, and sodium sulfate could also be used as sulfur sources. Utilization of a compound was quantified as the growth yield per mole of sulfur supplied. Yields were about 6 kg of protein per mol of sulfur. The product of the desulfuration of an s-triazine was identified as the corresponding hydroxy-derivative. This is the first substantiated report of the utilization of these s-triazines as sulfur sources by bacteria.

Human protein requirements: assessment of the adequacy of the current Recommended Dietary Allowance for dietary protein in elderly men and women

A continuous 30-day metabolic N balance study was conducted in seven elderly men (75 +/- 4 yr) and eight elderly women (78 +/- 9 yr) to evaluate the current protein Recommended Dietary Allowance for older men and women. The subjects received a diet providing 0.8 g egg protein (N x 6.25) kg-1 day-1. Energy intake computed to meet needs averaged 32 and 29 kcal kg-1 day-1 for males and females, respectively. N balances, including an estimate for integumental and other miscellaneous losses, were determined for the last 5 days of three consecutive 10-day diet periods and blood biochemical measurements were made at the end of each diet period. Three of seven males and four of eight females were not in body N balance during the final 5 days of the 30-day period. These N balance data indicate that 0.8 g egg protein kg-1 day-1 is not sufficient to achieve N equilibrium in a majority of subjects older than 70 yr and confirm the results and conclusions of a previous, short-term N balance study (Uauy et al., Am J Clin Nutr 1978;31:779-85). Hence, where energy intake approximates requirement, the current Recommended Dietary Allowance is not adequate for a majority of male and female subjects age 70 yr and above.

Nitrogen metabolism in preterm infants fed human donor breast milk: the possible essentiality of glycine.

Nitrogen metabolism was studied in three preterm infants (mean gestation 32 wk) by the method of consecutive metabolic balance. The absorption and retention of nitrogen from breast milk was measured, and protein turnover, synthesis, and breakdown were calculated from isotopic plateau of urinary urea and ammonia using an intermittent oral administration of 15N-glycine. Weight gain and nitrogen retention were compared with the weight gain and nitrogen accumulated for a foetus of equivalent gestational age in utero. The average composition of the milk was 289 +/- 19 KJ dl-1 and 1.44 +/- 24 g protein dl-1. The intake of energy was 572 +/- 61 KJ kg-1 day -1 and of nitrogen 447 +/- 99 mg kg-1 day-1. Stool output of nitrogen was 100 +/- 32 mg kg-1 day-1 giving an absorption of 348 +/- 78 mg kg-1 day-1, as urinary excretion was 91 +/- 17 mg kg-1 day-1 retained nitrogen was 256 +/- 71 mg kg-1 day-1, or 56% of intake. The specific weight gain was 15.6 +/- 2.6 g kg-1 day-1 and 53% of this comprised lean tissue (range 34 to 89%). In all but one study the postnatal retention of nitrogen fell far short of calculated in utero accumulation. The results of protein turnover were surprising. In six of the eight studies urinary urea failed to become enriched at all. Protein turnover calculated from the ammonia plateau was 1.94 +/- 0.54 g nitrogen kg-1 day-1, synthesis 10.9 +/- 3.4 g protein kg-1 day-1 and breakdown 9.3 +/- 3.4 g protein kg-1 day-1. It is concluded that the amino acid composition of breast milk may be inappropriate for supporting rates of lean tissue deposition equivalent to in utero accumulation.

Domesticated Proboscidea parviflora: a potential oilseed crop for arid lands

Wild and domesticated Proboscidea parviflora were evaluated as oilseed crops for arid lands through chemical and biological analyses. Domesticated plants grown in the Sonoran desert bore seed containing 35–40 per cent oil and 23–27 per cent protein. Yield per ha was estimated at 1000 kg of oil and 675 kg of protein, quantities which compare favourably with other crops. An ephemeral life cycle and certain characteristics of the fruit and seed allow this plant to grow in xeric habitats unsuitable for many other plants. Several Proboscidea species hybridize with P. parviflora and could be used in future crop breeding. Rapid germination and higher oil and protein content of seed make the domesticated P. parviflora superior to the wild form as a crop. Domesticated P. parviflora thus shows promise as an oilseed crop for the Sonoran Desert and possibly for other arid regions.

Desulfuration of Dialkyl Thiophosphoric Acids by a Pseudomonad

A strain of Pseudomonas acidovorans used the organophosphorus pesticide breakdown products, ionic O,O-diethyl phosphorothioate and ionic O,O-diethyl phosphorodithioate, as sulfur sources. The growth yields from the thiophosphates and sulfate were 3.6 to 4.1 kg of protein per mol of sulfur. Elemental sulfur and sulfide also served as sulfur sources but gave lower growth yields.

The effects of stocking rate and nitrogen fertilizer on the productivity of irrigated perennial pasture grazed by dairy cows. 2. Animal production

The relation between the stocking rate of dairy cows and their production from irrigated perennial pasture, with and without nitrogen (N) fertilizer, was studied over 2 years at Kyabram, Victoria. Pastures were rotationally grazed at stocking rates ranging from 4.4 to 8.6 cows ha-1. In each year, N treatments were topdressed four times at a rate of 56 kg N ha-1. For every additional cow per ha, production per ha decreased by 260 and 329 kg of milk, 12.3 and 15.5 kg of butterfat, and 10.7 and 14.5 kg of protein for years 1 and 2, respectively. In year one, the highest production of milk and butterfat (17,900 and 847 kg ha-1, respectively) was from cows stocked at 8.6 cows ha-1, and for protein (597 kg ha-1) from 7.6 cows ha-1. In year 2, production per ha of all milk products maximized and then declined. Maximum production of milk and butterfat (14,180 and 675 kg ha-1, respectively) was at 6.6 cows ha-1, and protein (508 kg ha-1) at 5.9 cows ha-1. Increasing stocking rate also reduced the liveweight of cows at all times. Topdressing with N fertilizer had no effect on total milk or butterfat production per cow, but consistently increased protein production. The range in response increased from 2 to 7 kg protein per cow at 4.4 and 8.6 cows ha-1, respectively. Application of N fertilizer increased liveweight per cow, with greater increases occurring at high stocking rates. In year 2, the efficiency of butterfat production over the whole year was 29.9, 29.3 and 37.0 kg of DM (pasture and supplements) per kg of butterfat produced for 4.4, 6.6 and 8.6 cows ha-1, respectively.

Kinetische untersuchungen der durch die cyclodextrin-glycosyltransferase katalysierten (1→4)-β-d-glucopyrano-syltransferreaktionen, insbesondere der zyklisierungs-reaktion, mit (1→4)-α-D-glucopyranosylketten “durchschnittlicher polymerisationsgrad von 16” als substrat

The transfer reactions, particularly the cyclization reaction, catalysed by the cyclodextrin glycosyltransferase {(1→4)-α-D-glucan:[(l→4)-α-D-glucopyranosyl]-transferase (cyclizing), EC 2.4.1.19; CGT} from Klebsiella pneumoniae M 5 al were studied with (1→4)-α-D-glucopyranosyl chains (d.p. 16). The initial rate of the cyclization reaction with substrate concentrations from 1 up to 16mM indicated a V of 6.2 kat &∣ kg-1 of protein and a molar catalytical activity of 421.6 kat &∣ mol-1 of enzyme. Km was found to be 1.03mM. In addition to the cyclization, CGT simultaneously catalysed a disproportionation of the substrate, yielding shorter maltooligosaccharides and (1→4)-α-D-glucopyranosyl chains which were significantly longer than the substrate itself. Cyclohepta- and cycloocta-amylose were accumulated in the course of longer incubation. They arose mainly from coupling reactions with the initially formed cyclohexaamylose and corresponding disproportionation of these transfer products. The extremely low formation rates of the higher cyclodextrins point to a “mistake” of the enzyme, when cyclizing to cyclohepta- and cyclooctamylose.

Body Composition of Dairy Cattle by Potassium-40 Liquid Scintillation Detection

Liquid scintillation detection by potassium-40 was used to estimate body composition of dairy cows of two ages and two yields. Average body weight, fat content, and protein content were 548kg, 27%, and 17%. First-calf cows had less body weight, less protein mass, and less fat mass than older cows, suggesting that heifers in first lactation continue to deposit protein and fat in later lactations. Production had no effect upon estimates of body composition. In response to lactation needs, there were average losses of about 50kg of fat and about 10kg of protein with marked variation among animals. Procedures preparatory to potassium-40 monitoring had no effect upon milk production. For estimating body composition in dairy cows liquid scintillation using potassium-40 detection appears to be nontraumatic and highly repeatable.

Three Mating Systems Compared: I. First-, Second-, and Third-Lactation Milk Yields, Composition, Flow, and Milking Times

Outcrossing, mild inbreeding, and crossbreeding in a common foundation of Holstein cows were compared in the Beltsville herd from 1957 through 1970. The outcross and mildly inbred systems consisted of four generations, and the crossbred system consisted of two- and three-breed crosses plus the Holstein backcrosses on the three-breed crosses. Sires for the outcross system were selected from among Holstein bulls in artificial insemination. Sires for the mildly inbred system were selected from bulls born in the Beltsville herd with daughters in other herds. Sires for the crossbred system were selected from Brown Swiss and Ayrshire bulls in artificial insemination and some of the Holstein bulls from the outcross system. All sires were selected on yield of milk of their daughters in other herds. Cows in the outcross system outproduced cows in the other two systems by 275 and 429kg of milk, 18 and 3kg of fat, 27 and 29kg of solids-not-fat and 11 and 7kg of protein. Cows in the crossbred system were .1 to .4% higher in percentage of components. Within the crossbred system, decreasing Holstein blood was associated with lower yield and higher percentages whereas the backcrosses were nearly equivalent to the Holstein outcrosses. Differences among generations within the outcross and mild inbred systems were small for traits of yield and components of milk. Differences among the three systems in two traits of rate of milking ranked as for milk yield.

Purification and properties of gamma-butyrobetaine hydroxylase from Pseudomonas sp AK 1.

gamma-Butyrobetaine hydroxylase (4-trimethylaminobutyrate, 2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating), EC 1.14.11.1) has been isolated from Pseudomonas sp AK 1 by ion-exchange, adsorption, and molecular-sieving chromatography. The preparation was homogeneous as judged from electrophoresis in agarose and polyacrylamide gels, isoelectric focusing, and equilibrium sedimentation. The molecular mass was 95 kdaltons as determined by sedimentation equilibrium centrifugation. From electrophoresis in polyacrylamide gel the molecular mass was estimated to 92 kdaltons, from gel filtration through columns of Sephadex G-200 to 86 kdaltons, and from gel filtration through thin layers of Sephadex G-150 and G-200 to 82 kdaltons. Calculation of molecular mass from Stokes radius, sedimentation coefficient, and partial specific volume gave a value of 96 kdaltons, and from the sedimentation coefficient, 93 kdaltons. Gel filtration through Sephadex G-200 in 6 M guanidinium chloride and electrophoresis in polyacrylamide gel containing 3.5 mM sodium dodecyl sulfate resulted in single bands with mobilities corresponding to molecular masses of 39 and 37 kdaltons, respectively, indicating that the enzyme is composed of two polypeptides chains with similar size. NH2-terminal amino acid sequencing in three cycles resulted in two amino acids in each cycle (Ala + Asn, Ala + Ile, Ala + Ile). The Stokes radius was 3.8 nm, corresponding to a diffusion coefficient of 5.7 X 10(-7) cm2/s. A sedimentation coefficient of 5.8 X 10(-13) s and a frictional ratio of 1.26 was found. The partial specific volume was 0.729 mL/g at 20 degrees C as calculated from amino acid analysis. The isoelectric point was 5.1, as determined by isoelectric focusing analysis. The light absorption in the ultraviolet and visible regions was that of a protein without light-absorbing prosthetic groups. The absorption coefficient at 280 nm of a 1.0% solution at pH 6.5 was 12.6. Amino acid analysis by ion-exchange chromatography showed a half-cystine content of 19 mol per 95 kg of protein (23 residues/1000). Thirteen sulfhydryl groups were found by colorimetric analysis before as well as after reduction with NaBH4, indicating absence of disulfide bonds. Less than 0.1 mol of iron was found per mol of enzyme.

A comparison of production costs and investment outlay effectiveness in the production of protein in 1969-1972

This paper aims at determining the effectiveness of the investment outlay and total production costs connected with obtaining and delivering to the wholesale market protein products derived from:- breeding farm animals in agriculture and processing them (meat, milk, eggs, broilers),- sea fisheries and fish processing industry (fishes and fish products).The calculation of costs and investment outlay has been carried out in reference to 1 kg of edible parts as well as to 1 kg of protein.

The relation of sodium and potassium ion transport to the respiration and adenine nucleotide content of liver slices treated with inhibitors of respiration.

1. The dependence of the net transport of Na(+) and K(+) by rat liver on the respiration has been determined by incubating slices in the presence of varying concentrations of respiratory inhibitors. 2. Neither the rate of net transport nor the total amount of each ion transported was inhibited unless the rate of endogenous respiration was decreased below a critical value of about 330mmol of O(2)/h per kg of protein (i.e. 50% of the total endogenous respiration). 3. The uninhibited rate of respiration could be varied over a twofold range (380-770mmol of O(2)/h per kg of protein) by the use of different substrates, but the critical value for the onset of transport inhibition was quite constant (290-360mmol/h per kg of protein) under these different conditions. 4. Slices incubated at 38 degrees C without inhibitors showed an increase of their ATP content and the concentration ratio ATP/ADP. The final ATP content and concentration ratio, ATP/ADP, of slices treated with different concentrations of inhibitors were closely related to the rate of respiration. 5. The increased ATP content of the control slices during incubation was equal to the increase of total adenine nucleotides. At increasing degrees of respiratory inhibition the relative contributions of ADP and AMP to the total adenine nucleotide content increased. 6. The critical rate of respiration for the onset of inhibition of ion transport and the corresponding contents of adenine nucleotides provide estimates of the maximal values of certain parameters of energy metabolism required for the support of alkali-cation transport in the liver slices.

Studies on human intestinal proteolysis.

The enzymic digestion of protein to acid-soluble peptides has been measured in the ileal drainage material from human subjects in whom an ileostomy was established for the treatment of ulcerative colitis or polyposis coli. This activity (TPA) is sensitive to dietary protein but insensitive to fat and carbohydrate, and follows a diurnal rhythm with increased enzyme output during the night. Two-thirds of this proteolytic activity is due to the pancreactic enzymes trypsin and chymotrypsin. Experiments with neomycin sulphate suggest that not more than 7 per cent is due to bacterial enzymes. No contribution appeared to be made by small intestinal epithelium, and it is considered that the remainder of this activity can be ascribed to other pancreatic enzymes. The faecal output of TPA in two subjects before operation was considerably less than that from their ileostomy when this was later established. Reasons are presented for believing the human small intestine capable of digesting several kg of protein daily. ...