Trypsin Units Research Articles

Trypsin Inhibitor Assay: Expressing, Calculating, and Standardizing Inhibitor Activity in Absolute Amounts of Trypsin Inhibited or Trypsin Inhibitors

AbstractFor expressing trypsin inhibitor activity (TIA), trypsin units inhibited (TUI), trypsin inhibited, and trypsin inhibitors have been used. Although the last two units are preferred, their calculations in current practices require refinement. With the proposed AOCS method Ba 12a‐2020, four experiments were conducted, using four trypsin preparations having specific activity of 11,625, 12,602, 13,728, and 14,926 Nα‐benzoyl‐L‐arginine ethyl ester (BAEE) units/mg protein, respectively. Experiment 1 determined the relationship between absorbance at 410 nm (A410) and trypsin concentration. Experiment 2 involved assaying raw and heated soybeans, expressing TIA as TUI/mg sample and μg trypsin inhibited/mg sample, and determining conversion factors between the two units. Experiment 3 resembled Experiment 2 except for using purified soybean Kunitz inhibitor (KTI) and Bowman‐Birk inhibitor (BBI). Conversion factors determined correlated highly with trypsin‐specific activity (R2 = 0.9789). After standardizing against a reference trypsin having 15,000 BAEE units/mg protein, a standardized conversion factor of 0.03 A410 (1.5 TUI) = 1 μg trypsin inhibited was determined. It remained consistent regardless of trypsin specific activity, with or without inhibitors, and type of inhibitor samples. By using purified inhibitors (Experiment 3), conversion values between TUI and μg trypsin inhibitor and between μg trypsin inhibited and μg trypsin inhibitor could also be calculated, enabling expression of TIA in amounts of pure KTI, BBI or their equivalents. Furthermore, when the AOCS method was modified with half substrate concentration, half trypsin concentration or half both (Experiment 4), TIA values in TUI could change with modifications but values in mg trypsin inhibited (standardized) or trypsin inhibitor remained consistent.

들깨박으로부터 항산화 가수분해물 생산을 위한 단백질 추출 및 trypsin 가수분해 조건

Perilla seed meal (PSM) is an agricultural by-product that contains a lot of functional substances and protein, and is thus a functional food material. This study aimed to determine the optimal conditions of protein extraction and enzymatic hydrolysis required to produce hydrolysate with antioxidant activity from PSM. We determined the optimal conditions required to extract proteins from PSM by measuring the browning degree and protein content of extracts obtained at pH 5 and of precipitates at pH 3. The protein yield and content were high (67.3% and 109.2 mg/g, respectively), and the browning degree was low (1.00) after extraction at pH 10 and precipitation at pH 4. We hydrolyzed PSM protein with trypsin at various concentrations for different periods to establish the optimal hydrolysis conditions needed to produce PSM protein hydrolysates with antioxidant activity. The antioxidant activity was maximal in hydrolysates obtained by incubation for 3 h with 25 units of trypsin. Therefore, the optimal conditions required to extract protein from PSM comprised extraction at pH 10, precipitation at pH 4, and enzymatic hydrolysis with 25 units of trypsin for 3 h.

Trypsin Inhibitor Assessment with Biochemical and Molecular Markers in a Soybean Germplasm Collection and Hybrid Populations for Seed Quality Improvement

A soybean germplasm collection was studied for the identification of accessions with low trypsin inhibitor content in seeds. Twenty-nine accessions, parental plants, and two hybrid populations were selected and analyzed using genetic markers for alleles of the Ti3 locus, encoding Kunitz trypsin inhibitor (KTI). Most of the accessions had high or very high KTI (49.22–73.53 Trypsin units inhibited (TUI/mg seeds), while the two local Kazakh cultivars, Lastochka and Ivushka, were found to have a moderately high content of KTI, at 54.16–54.87 TUI/mg. In contrast, two soybean cultivars from Italy, Hilario and Ascasubi, showed the lowest levels of trypsin units inhibited, at 25.47–27.87 TUI/mg. Electrophoresis of seed proteins in a non-denaturing system showed a simple discrimination pattern and very clear presence/absence of bands corresponding to KTI. The SSR marker Satt228 was the most effective diagnostic marker among the three examined, and it confirmed the presence of the homozygous null-allele ti3/ti3 in cultivars Ascasubi and Hilario, which were used for hybridization with the local cv. Lastochka. Heterozygote F1 hybrid plants and homozygous ti3/ti3 lines in F2 segregating populations were successfully identified using Satt228. Finally, through marker-assisted selection with Satt228, prospective homozygous ti3/ti3 lines were produced for further application in the breeding program aimed at improving soybean seed quality in Kazakhstan.

Uncertainty analysis of the microtiter plate method for determining trypsin inhibitor activity

Protease inhibitor activity is frequently measured in legume seeds as protease inhibitors are thought to have anti-nutritional as well as anti-carcinogenic properties. Trypsin inhibitor activity (TIA) can be measured using different methods. The microtiter plate method is very convenient and routinely used; therefore, in this study, we analyzed the measurement uncertainty of the microtiter plate method to understand what affects the measurement results, as well as to compare TIA values obtained by similar and different methods. For uncertainty analysis of TIA measurement, we used the soybean variety ‘Vojvodjanka,’ which is known to have TIA greater than 80 trypsin units inhibited (TUI) per mg of seed. We followed the Guide to the Expression of Uncertainty in Measurement (GUM) for our uncertainty analysis of the microtiter plate method for TIA testing, which we present in the form of an uncertainty budget. Absorbance measurement and preparation of sample reaction mixture took the largest percent (71 %) of overall uncertainty of TIA value. The TIA of soybean variety ‘Vojvodjanka’ was (94.1 ± 8.4) TUI/mg, and this result is consistent with those obtained by other authors. The microtiter plate method is a reliable method for TIA measurement, making seed quality testing more efficient.

Live attenuated influenza viruses produced in a suspension process with avian AGE1.CR.pIX cells.

BackgroundCurrent influenza vaccines are trivalent or quadrivalent inactivated split or subunit vaccines administered intramuscularly, or live attenuated influenza vaccines (LAIV) adapted to replicate at temperatures below body temperature and administered intranasally. Both vaccines are considered safe and efficient, but due to differences in specific properties may complement each other to ensure reliable vaccine coverage. By now, licensed LAIV are produced in embryonated chicken eggs. In the near future influenza vaccines for human use will also be available from adherent MDCK or Vero cell cultures, but a scalable suspension process may facilitate production and supply with vaccines.ResultsWe evaluated the production of cold-adapted human influenza virus strains in the duck suspension cell line AGE1.CR.pIX using a chemically-defined medium. One cold-adapted A (H1N1) and one cold-adapted B virus strain was tested, as well as the reference strain A/PR/8/34 (H1N1). It is shown that a medium exchange is not required for infection and that maximum virus titers are obtained for 1 × 10-6 trypsin units per cell. 1 L bioreactor cultivations showed that 4 × 106 cells/mL can be infected without a cell density effect achieving titers of 1 × 108 virions/mL after 24 h.ConclusionsOverall, this study demonstrates that AGE1.CR.pIX cells support replication of LAIV strains in a chemically-defined medium using a simple process without medium exchanges. Moreover, the process is fast with peak titers obtained 24 h post infection and easily scalable to industrial volumes as neither microcarriers nor medium replacements are required.

The Plasticity of the β-Trefoil Fold Constitutes an Evolutionary Platform for Protease Inhibition

Proteases carry out a number of crucial functions inside and outside the cell. To protect the cells against the potentially lethal activities of these enzymes, specific inhibitors are produced to tightly regulate the protease activity. Independent reports suggest that the Kunitz-soybean trypsin inhibitor (STI) family has the potential to inhibit proteases with different specificities. In this study, we use a combination of biophysical methods to define the structural basis of the interaction of papaya protease inhibitor (PPI) with serine proteases. We show that PPI is a multiple-headed inhibitor; a single PPI molecule can bind two trypsin units at the same time. Based on sequence and structural analysis, we hypothesize that the inherent plasticity of the β-trefoil fold is paramount in the functional evolution of this family toward multiple protease inhibition.

Protease-Activated Receptor-2 Activation: A Major Role in the Pathogenesis of Porphyromonas gingivalis Infection

Protease-Activated Receptor-2 Activation: A Major Role in the Pathogenesis of Porphyromonas gingivalis Infection

GSH Inhibits Trypsinization of the C-terminal Half of Human MRP1

MRP1 is a 190-kDa membrane glycoprotein that confers multidrug resistance to tumor cells. The accumulated evidence has proved that GSH interacts with MRP1 and stimulates drug transport. However, the mechanism of GSH-dependent drug transport by MRP1 remains unclear. In this study, we used limited tryptic digestion of MRP1 in isolated membrane vesicles, in the presence and absence of GSH, to investigate the influence of GSH on MRP1 conformation. We found that GSH inhibited the generation of an approximately 35-kDa C-terminal tryptic fragment (including a C-terminal His tag) termed C2 from MRP1. This effect of GSH was not because of direct inhibition of trypsin activity, and agosterol A enhanced the inhibitory effect of GSH. The main cleavage site in MRP1 for the generation of the C2 fragment by trypsin resided between TMD2 and NBD2 of MRP1. Limited tryptic digestion of membrane vesicles expressing various truncated and co-expressed MRP1 fragments in the presence and absence of GSH revealed that GSH inhibited the production of the C2 fragment only in the presence of the L(0) region of MRP1. Thus the L(0) region is required for the inhibition of trypsinization of the C-terminal half of MRP1 by GSH. These findings, together with previous reports, suggest that GSH induces a conformational change at a site within the MRP1 that is indispensable for the interaction of MRP1 with its substrates.

In vitro uptake and stability study of pVEC and its all-D analog.

A key step in the development of new hydrophilic pharmaceuticals is to get them through biological barriers. Cell-penetrating peptides, CPPs, have been shown previously to enter cells both in vitro and in vivo by a non-endocytotic mechanism and to be able to carry large cargo molecules with them. Recently, we showed that a small peptide, pVEC, from murine vascular endothelial cadherin, has the characteristics to be classified as a protein derived CPP. Here we have further investigated pVEC together with its all-D analog for cellular uptake, intra- and extracellular stability, and their enzymatic degradation. The two peptides, pVEC and all-D pVEC, translocate into aortic endothelial cells and murine fibroblasts by a non-endocytotic mechanism. In phosphate buffer, pVEC remains intact while the C-terminal lysine is quickly removed in human serum and serum-containing media. Both pVEC and pVEC without the C-terminal Lys were detected by mass spectrometry inside the two cell types tested. The pVEC half-life is 10.5 min in phosphate buffer containing 10 units of trypsin and 44.6 min in phosphate buffer containing 4.2 units of carboxypeptidase A and 18 units of carboxypeptidase B. In contrast topVEC, the all-D analog remains intact in serum and resists enzymatic degradation.

Effects of heat treatment and substitution level on palatability and nutritional value of soy defatted flour in feeds for Coho Salmon, Oncorhynchus kisutch

An in vivo digestibility trial and a feeding trial were conducted to determine the extent to which heat treatment, nutritional quality, and palatability of hexane-extracted, defatted soy flour (SF) influenced growth of fingerling coho salmon. Heat treatment of SF (autoclave, 1.7 atm, 121°C) lowered trypsin units inhibited (TUI) from 181 to 1.8 after 20 min and lowered protein solubility from 98% to 70%. Longer heating periods further reduced SF protein solubility, but did not substantially reduce TUI. The apparent digestibility coefficient (ADC) of protein from heated SF (90.8) was significantly higher than the ADC of unheated SF (74.3), but significantly lower than the ADC of the wheat gluten basal diet (98.2). In the feeding trial, fish weight gain was reduced in a step-wise fashion at each level (15, 20, or 25%) of unheated SF inclusion in the diet. Fish fed diets containing heat-treated SF gained more weight at each SF inclusion level compared to their corresponding unheated treatment groups, but inclusion of heat-treated SF greater than 15% substitution of herring meal protein resulted in reduced weight gain compared to fish fed the control diet. Krill supplementation (5%, combination of dried and frozen) increased weight gain in fish fed diets containing 25% heated or unheated SF, primarily by restoring feed intake. In fish fed the heated 25% SF diet with krill, feed intake and average weight gains were equivalent to control diet levels. Fish fed the unheated SF diet with added krill had higher feed intake and weight gains than fish fed the equivalent diet without added krill, but gains were significantly lower than controls. Calculated indices of fish performance, e.g., specific growth rates, feed conversion ratios, protein retention ratios, and apparent net protein utilization (percentage protein retention) displayed patterns similar to weight gain results. In this study, a 20 min heat treatment of SF reduced trypsin inhibitor activity to physiologically insignificant levels, increased protein digestibility, and also allowed a successful 15% substitution of SF for herring meal protein. It appears that reduced feed intake associated with unheated SF was responsible for approximately one-half of the observed reduction in weight gain. Lower nutritional value of the unheated or insufficiently heated SF was responsible for the remaining reduction in fish performance. Therefore, a combination of proper heat treatment and supplementation with palatability-enhancing feed ingredients can overcome these problems, even in young Pacific salmon which are known to be extremely sensitive to soybean meal in their feeds.

Some compositional properties of seeds and oils of eightAmaranthus species

AbstractGrain of 21Amaranthus accessions (eight species) was analyzed for crude fat, fatty acid profiles (FAP), and vitamin E (tocopherols and tocotrienols). Contents of (1→3), (1→4) β‐glucan were determined in 12 accessions (four species), and trypsin inhibitor activity (TIA) in 20 accessions (six species). FAP and vitamin E profiles were compared to those of barley, buckwheat, corn, lupin, oat, and wheat oils. Crude fat content ranged from 5.2 to 7.7%, and of the oils examined, amaranth oil was most similar in FAP to corn and buckwheat oils. Amaranth was higher than all but wheat and lupin in tocopherol content but was virtually devoid of tocotrienols, which have been shown to have hypocholesterolemic activity. Amaranth grain did not contain (1→3), (1→4) β‐glucans and was low in trypsin inhibitor activity (≤4.3 trypsin units inhibited/mg). Any hypocholesterolemic effects of dietary amaranth are apparently due to substances other than (1→3), (1→4) β‐glucans or tocotrienols.

Biodegradation of the cross-linked cationic poly(amino acid) hydrogels by proteolytic enzymes

The degradation of the cross-linked cationic poly(amino acid)-glutaraldehyde (GA) hydrogels by some proteolytic enzymes has been investigated using lysine (Lys)- and ornithine (Orn)-containing homo- and copolypeptides. From the experimental results, the following findings were obtained. The polylysine (PLL)-glutaraldehyde (GA) gels are degraded by trypsin, but not by chymotrypsin and papain. Optimal conditions for degradation of the PLL-GA gels are trypsin units over 500, pH 7-11, 0.5-2 M salts, and higher reaction temperatures. A pH region below 5 and a salt concentration over 4 M inhibit trypsin activity toward the PLL-GA gels. Copoly(Lys 1 -Tyr 1 )-GA gels are degradable by trypsin, chymotrypsin, and even papain. Polyornithine (PLO) gels behave like PLL gels but exhibit no degradation by enzymes. Copoly(Lys 1 -Orn 1 ) gels are degradable by trypsin, suggesting potential for a controlled biodegradation. The results might offer some clues to the understanding of the degradation of natural protein adhesives.

Some compositional properties of camelina (camelina sativa L. Crantz) seeds and oils

AbstractFatty acid profiles (FAP), tocopherol (T), and tocotrienol (T3) contents, total lipid contents, and trypsin inhibitor activity were quantitated from thirteen accessions of camelina (Camelina sativa L. Crantz), a little‐known oilseed. Camelina seeds of ten accessions were also assayed for ß‐glucans. FAP (%) of camelina oils were: oleic (14.1 to 19.5), linoleic (18.8 to 24.0), linolenic (27.0 to 34.7), eicosenoic (12.0 to 14.9), erucic (0.0 to 4.0), all others (11.8 to 17.4). Camelina oil T and T3 contents (mg/100 g) were: αT (0.66 to 2.38), ßT (0.38 to 1.45), γT/ßt3 (4.37 to 18.68), δT (0.00 to 0.48), γT3 (0.00 to 0.79), γT3 (0.00), γT3 (0.00). Total tocols were higher in camelina than in canola, crambe, flax, soybean, and sunflower, with γT/ßT3 constituting 82% of total tocols. The oil content of camelina seeds ranged from 29.9 to 38.3%. Camelina seeds did not contain ß‐glucans. Trypsin units inhibited ranged from 12 to 28 compared to 111 for raw soybean.

Antenatal microbiologic and maternal risk factors associated with prematurity

In a prospective study of 202 women (gestational age 24 +/- 4 weeks), we evaluated possible influences of lower genital tract infection or bacterial conditions on obstetric outcomes, including preterm labor, preterm premature rupture of membranes, and preterm birth. The presence of bacterial vaginosis (18.7%) was associated with an increased risk of preterm labor (relative risk, 2.6; 95% confidence interval, 1.08 to 6.46). For women with bacterial vaginosis who also had Mobiluncus species morphotypes identified on Gram stain, the relative risk of preterm labor was 3.8 (95% confidence interval, 1.32 to 11.5). Presence of vaginal Mycoplasma hominis (10.8% of patients) was associated with both preterm labor (relative risk, 1.8; 95% confidence interval, 0.77 to 4.4) and preterm birth (relative risk, 5.1; 95% confidence interval, 1.45 to 17.9). Recovery of Staphylococcus aureus (3.0%) was associated with preterm labor (relative risk, 3.1; 95% confidence interval 1.12 to 8.7). Identification of two or more bacterial-linked abnormalities was also associated with preterm labor (relative risk, 3.3; 95% confidence interval, 1.44 to 7.58). An increased level of vaginal wash protease (greater than or equal to 10 trypsin units) (16%) was associated with preterm labor and was noted in 50% of women with preterm premature rupture of membranes. A history of prior preterm birth was the single best historical predictor of both preterm labor (relative risk, 3.6; 95% confidence interval, 1.92 to 6.83) and preterm birth (relative risk, 6.7; 95% confidence interval, 2.2 to 20.4). History of three or more abortions, antenatal urinary tract infection, and occurrence of medical complications during pregnancy also correlated with increased risk of preterm labor. These findings affirm and refine associations of various maternal reproductive tract infections with preterm labor, premature rupture of membranes, and birth, allowing for controlled treatment trials aimed at prevention of preterm birth.

Antenatal microbiologic and maternal risk factors associated with prematurity

In a prospective study of 202 women (gestational age 24 ± 4 weeks), we evaluated possible influences of lower genital tract infection or bacterial conditions on obstetric outcomes, including preterm labor, preterm premature rupture of membranes, and preterm birth. The presence of bacterial vaginosis (18.7%) was associated with an increased risk of preterm labor (relative risk, 2.6; 95% confidence interval, 1.08 to 6.46). For women with bacterial vaginosis who also had Mobiluncus species morphotypes identified on Gram stain, the relative risk of preterm labor was 3.8 (95% confidence interval, 1.32 to 11.5). Presence of vaginal Mycoplasma hominis (10.8% of patients) was associated with both preterm labor (relative risk, 1.8; 95% confidence interval, 0.77 to 4.4) and preterm birth (relative risk, 5.1; 95% confidence interval, 1.45 to 17.9). Recovery of Staphylococcus aureus (3.0%) was associated with preterm labor (relative risk, 3.1; 95% confidence interval 1.12 to 8.7). Identification of two or more bacterial-linked abnormalities was also associated with preterm labor (relative risk, 3.3; 95% confidence interval, 1.44 to 7.58). An increased level of vaginal wash protease (?10 trypsin units) (16%) was associated with preterm labor and was noted in 50% of women with preterm premature rupture of membranes. A history of prior preterm birth was the single best historical predictor of both preterm labor (relative risk, 3.6; 95% confidence interval, 1.92 to 6.83) and preterm birth (relative risk, 6.7; 95% confidence interval, 2.2 to 20.4). History of three or more abortions, antenatal urinary tract infection, and occurrence of medical complications during pregnancy also correlated with increased risk of preterm labor. These findings affirm and refine associations of various maternal reproductive tract infections with preterm labor, premature rupture of membranes, and birth, allowing for controlled treatment trials aimed at prevention of preterm birth. (Ann J OBSTET GYNECOL 1990;163:1465-73.)

Nutritional and anti‐nutritional characteristics of mucuna (Mucuna utilis) bean seeds

AbstractSome nutritional and anti‐nutritional characteristics of mucuna (Mucuna utilis (Wight) Burck) bean seeds were studied. The mature seeds contained 264 g crude protein, 63 g crude fibre, 41 g crude fat, 37 g ash and 595 g carbohydrates kg−1 DM. The essential amino acid profile compared well with the FAO/WHO scoring pattern except for a deficiency of sulphur‐containing amino acids. Mineral composition was similar to those reported for most tropical grain legumes.Raw mucuna seed samples contained moderately high levels of anti‐tryptic activity (2170 trypsin units inhibited g−1 DM), but this was completely destroyed by cooking. The other anti‐nutritional factors (phytate, cyanide and tannins) are probably of little nutritional significance provided that the beans are properly processed. The in‐vitro protein digestibility of raw and cooked beans were 71·5 and 80·3 %, respectively. In view of the high L‐DOPA contents reported in some mucuna cultivars, overconsumption of mucuna beans should be viewed with some caution until suitable processing methods are developed.

Novel cationic triazine dyes for protein purification

The effectiveness of a new immobilized cationic triazine dye was investigated alongside two new amphoteric triazine dyes and two well known anionic triazine dyes, Procion Red H-3B and Procion Blue H-B, as chromatographic media for binding four familiar proteases-trypsin, chymotrypsin, thrombin and carboxypeptidase-B-as well as a typical oxidoreductase, lactate dehydrogenase, and human serum albumin. The new affinity adsorbent, CL-Sepharose-immobilized Cationic Dye, specifically binds trypsin-like proteases such as trypsin, thrombin, and carboxypeptidase-B, but none of the other proteins tested. In contrast, the amphoteric and anionic immobilized dyes bind all the other proteins tested in a similar fashion. The specificity of the cationic dye was exploited in the resolution of trypsin and chymotrypsin from a crude activated bovine pancreatic extract. The procedure described here affords trypsin with specific activity of 7400 units/mg with a 79% overall yield in a single step. The immobilized cationic dye, unlike previously reported adsorbents for trypsin, is inexpensive, readily synthesized, and displays a workable capacity of 4000 trypsin units or 0.55 mg protein/g moist weight gel (1.2 mumol dye/g moist weight gel) from a crude bovine pancreatic extract and, thus, is potentially amenable to process-scale operations.

Investigations on the trypsin inhibitor, urease and cooking behaviour of soybean Glycine max Merr.

Eleven varieties of soybeans were analysed for their trypsin inhibitor activity (TIA), urease activity and cooking behaviour. The TIA ranged between 8·1 and 38·5 trypsin units inhibited per mg meal. In general, black soybeans contain higher trypsin inhibitor activities than yellow varieties. There was no appreciable variation in urease activity whose values ranged between 1·93 and 2·12 pH units. Considerable variability was evident in cooking behaviour of soybeans. The cooking period ranged between 140 min and 318 min. Thus the present study suggests the possibility of lowering trypsin inhibitor activity and cooking periods by further selection and breeding programmes of soybean cultivars.

Investigations on the trypsin inhibitor, hemagglutinin, phytic and tannic acid contents of cowpea Vigna unguiculata

Ten cultivated varieties of mature dry beans Vigna unguiculata were analysed for trypsin inhibitor (TI) and hemagglutinating activities, phytic acid, phytic acid-phosphorus and tannic acid. The respective concentrations were: 19·6–28·2 TUI mg −1 protein, ∗ ∗ Trypsin units inhibited (TUI) per mg protein, as defined by Kakade et al. (1969). 33·5–98·9 HU mg −1 protein, † † Hemagglutinating units (HU) per mg protein, as defined by Liener (1955). 280–331 mg 100 g −1, 131–200 mg 100 g −1 and 0·42–0·78 g 100 g −1 dry weight. Phytic acid-phosphorus as a percentage of total phosphorus was highest in Farv-13 (49·9) and lowest in Samaru local (29·8). Considerable variability in hemagglutinating activity was evident among the different varieties as indicated by the high percentage co-efficient of variation. Some of these differences may be genetic and may provide an opportunity for the genetic development of cowpea strains with superior protein quality, low in hemagglutinin content.

Protein Quality of Triticale. II. Prediction of Protein Efficiency Indices Through Chemical Analyses1

Several chemical determinations of triticale (✕ Triticosecale Wittmack) meals have shown promise of predicting protein efficiency indices (PEI = g body weight gain per g protein consumed) as determined by Microtus bioassay. The percent water‐soluble protein (pH 4.9), total trypsin units inhibited (total TUI, adjusted for percent water‐soluble protein), and extracted dye‐binding capacity (DBC completed after removal of water‐soluble proteins) showed the highest correlations with PEI. A group of 42 F4 winter triticale plants representing seven F4 plants from each of two high F3 PEI plants, two average F3 PEI plants and two low F3 PEI plants, were analyzed. The correlations with PEI were −0.45, −0.53, and 0.66 (P<0.01) for percent water‐soluble protein, total TUI, and extracted DBC, respectively. The multiple correlation coefficient utilizing total TUI and extracted DBC was 0.74**.A group of 20 F3 plants selected for high and low PEI values gave even more predictable responses. Their correlations with PEI were −0.71, −0.79, and 0.66 for percent water‐soluble protein, total TUI, and extracted DBC, respectively. The multiple correlation coefficient for the regression of extracted DBC and total TUI on PEI was 0.86**, indicating that 75% of the variation in PEI was accounted for by the two independent variables.